Timber Frame Base for Log Cabins

I’ve been pondering this post and am slightly reluctant to write it as I am NOT a structural engineer. I have lots of experience with timber but I am not at all qualified to give technical advice and specifications, so please read this post in the spirit it is meant.

You have no come back on me personally if anything goes wrong, the design of this is completely down to you but I will give some advice and ideas based on my experience.

Since I highlighted this type of base in my log cabin base requirements  page we get lots of questions on my very favourite base:

The timber frame base for log cabins.

What I love about a timber frame base is that:

  • It can be moved.
  • It’s truly a temporary structure which is great in certain circumstances.
  • It allows air flow and therefore the timber will never rot even if it’s not treated.
  • It’s very easy to create a level base in very unlevel areas.
  • It’s a cheap solution in inaccessible areas for concrete.
  • Cheap overall.
  • If subsidence occurs you can simply jack up the area concerned and re-pin.
  • A good system when flooding occurs naturally and does not affect it’s environment.

No doubt you’ve done some research on all the types of bases you can use. You’ll have perhaps come across various types of pads, plastic grills, jack type things, easy bases, there’s all sorts of gadgetry out there. If concrete or paving slabs is not a solution for you you can’t beat good ol’ wood over all the gadgets and alternatives there are.

Stick to Wood

My advice is to stick with wood and don’t waste your money on the gadgets, you know where you are with a good lump of wood:

  • It’s relatively cheap when compared to other ‘gadgets’
  • If treated and looked after it lasts forever (ish)
  • If anything needs replacing you can do so easily.
  • If you need more it’s readily available.

A timber frame used as a base for a log cabin does not need fancy timber, rough sawn from your local builder merchant is perfectly adequate but it would ideally be pressure treated (tanalised – More information on tanalised timber)

What size timber to use?

I’m often asked what size timber to use, as I mentioned, I’m not a qualified engineer, don’t necessarily go by my advice but I like big, chunky and manly bits of wood. Something like 150mm x 50mm and then laminated and used under every log forming 150mm x 100mm, sometimes for bigger buildings even bigger. I don’t have structural calculations, this is all touch and feel. I think anyone with any slight experience can look at a piece of timber and decide if it’s strong enough.

Here’s a base I was involved in:

This is the start of a timber frame base for a log cabin. Notice the size of the timber we are using, this has been laminated together to form the frame.

This is the start of a timber frame base for a log cabin. Notice the size of the timber we are using, this has been laminated together to form the frame.

This base went on to support one of our biggest standard log cabins: The Edelweiss 70mm log cabin You can see here how we have joined wood together to form the main frame. Sometimes you can do it in two sections, two rectangles and then join them together. Notice also the posts we are using, I like big and these are nice big lumps of timber. Alternatively though you can also laminate your timber to make these. I prefer to see the support posts directly under a join as you know it is always going to be supported if screws or bolts fail.

This was another one I was involved in, this example was not actually for a log cabin but the same principle applies:

Posts are longer so we introduced some lateral bracing

Posts are longer so we introduced some lateral bracing

Notice how the post supports are under the joins in the corner and middle. This one was made in two rectangles and joined together in the center. As your support legs get longer lateral bracing is a good thing to consider.

Supporting your timber frame base

I’ve tried a few things in the past and looked at a few more. I’ve had a go with the plastic grids you can get but I still don’t really see the point of them apart from they’re a bit lighter but I worry about the longevity of them. Great in a greenhouse but I still think you can’t beat a nice solid slab on a bed of sand, or sand and cement. Make sure though of the stability of the ground underneath as you don’t really want subsidence in years to come.

A suggestion on a good timber framed base

This is just a suggestion on how I would build a timber frame base for your log cabin, it’s not gospel, it may be wrong, remember I’m not a structural engineer or a qualified landscaper so you need to design your own way of doing it. My ideas might help though.

Timber frame base example of the way I might do it depending of course on the size of building

Timber frame base example of the way I might do it depending of course on the size of building

This is just an example and my personal thoughts (you may have your own) on how to make a good timber frame base for your log cabin. The main points in my personal design are:

  • I’m using a standard size timber, all of the same size, maybe 150mm x 50mm (6″ x 2″)
  • Laminated around the perimeter of the cabin walls for strength – Basically I am screwing / bolting with coach bolts the timber together every 1m or so. For bigger buildings I might use thicker timber. Every wall will have this support under it.
  • I’m using chunky support posts under the joints. Either use big 12cm timber posts like we supply or consider laminating.
  • You may want to consider, depending on the size of your building, using noggins to stop lateral movements of the joists
  • Incorporate your floor joists within the timber frame base. Our floor packs for log cabins are designed only for a flat and level base such as concrete or paving slabs. Joist in your house are normally spaced at about 300mm apart, it’s a good idea to use this measurement in your log cabin floor. If you are using the cabin for heavier items, treadmills, heavy machinery etc, you may want to consider them closer.
  • You will NOT need to use foundation beams under the first log. The sole purpose of them is to keep the first log away from ground contact, you are already accomplishing this with a timber frame base for your log cabin. With joists incorporated in the frame this will also give a better finish and everything will be at the same level.
  • The outside of the timber frame should be identical to the footprint listed with every log cabin to properly support the log, bear in mind the log thickness of your building though as it’s good to have a lip on the inside of at least 25mm for the floor to sit on.
  • If you feel like being clever bring the frame in by 2 – 5mm from the footprint and this will then set the frame in slightly giving a drip for the logs and you can be sure water will never sit against the first log
  • Consider using joist hangers for the floor joists as these will be easier and quicker.
  • If your post supports are above 300mm I would start to consider lateral supports to stop any movement.
  • Consider your spacing of posts support. I like to support every 1.50m depending on the building and thickness of timber.
  • Consider using Weed Control Matting under the base – nettles grow anywhere!

That’s pretty much it as far as I’m going to help you.

Hopefully you now have some ideas of your own. The principle is quite simple. Make a frame for your log cabin to sit on, make sure it does not subside, make sure the wall logs are supported. Above all make sure it is properly, 100% level! Oh and jump on your frame before installation – this is my technical test to check whether it will work 🙂

 Some examples of timber frame bases for Log Cabins

Here’s some examples of what others have done, all of them work. It’s up to you what information or ideas you take from this post ……

This is at the shallow end

This is at the shallow end of a build, notice the use of noggins to stabilise lateral movement of the floor joists.

The higher end

The higher end of the project. A timber frame helps you level out a very unlevel piece of ground and often cheaper. Notice the supports are smaller but a lot more of them. I have experimented in the past with simple stakes in the ground – lots of them but it worked well. This is what is happening here.

Perfect

Perfect! I love this base, massive telegraph poles as supports, good chunky timber and floor joists on hangers.

Smallr

Smaller timbers are used here, this customer has used a different support system and is screwed in from the side, it’s working and nothing wrong with it. It can also be adjusted easily.

same

This is the same customer as above, he created the frame, built the cabin and is now going to put in the joists. A good idea to do it afterwards as it does not hamper your build of the main log cabin.

Floor joists

Floor joists are now being added. I would have liked them closer together but of course it does depend on the thickness of your floor / decking boards you are going to use. There’s no right or wrong answer when it comes to a timber framed base.

floor

Floor going in on top of the floor joists.

post

Here you can see some chunky posts which I like, they’re also using large rough sawn timber with joist hangers for ease. After the build you would then clad this to make it look pretty. This is our Torsten Log cabin

osb

You can see here the floor joists used on joist hangers supporting an OSB floor used because they are going to put a final floor covering down so they do not need our posh Spruce timber floor.

detail

Noggins being used to stop the lateral movement of the floor joists. See also how thick the timber is in the frame

post

Again see the size of timber being used. Timber frames do get you out of a levelling problem and save quite a bit of money, it’s worth considering.

intersting

Not a timber frame but an interesting consideration, this customer is using up stand slabs and then using joist hangers to support the floor joist.

floor

A joist system has been created with a timber floor on top before the cabin is put on top – interesting and clever!

Joists

The base I was involved in being extended with noggins, joist hangers and supports and following a system we had put in place to extend further.

pretty

I love a timber framed base, so much can be accomplished. This does look good!

This post is not official advice, it’s nothing to do with Tuin or Tuindeco, all mine and I often get things wrong (so my wife says) take from it what you can but a timber frame base for your log cabin can get you out of a lot of problems and expense.

I hope you have some ideas? If you do please share them.

To make leveling the base we do have a nice product. It’s not a bad price either and you can level between 30mm and 140mm using a combination of two units click on the picture for more details:

Very useful pads for easily supporting and leveling a timber frame base for your log cabin

Very useful pads for easily supporting and leveling a timber frame base for your log cabin

More examples:

Croft Log Cabin

This is going to be one of my favourite post and I know I’m going to enjoy writing it as it centres around a personal dream of mine. I would love to do what this lovely customer and her family are doing.

Mrs N, quoted as being an ‘Open Minded Mum’. Pooled resources with her daughter in law and son to ‘share energy sources (ground source heat pump, wind turbine etc) and to share work on a smallholding’. They bought a 64 acre croft together!

Please see Mrs N’s daughter in law’s blog for a really lovely story and some amazing pictures and my favoured base system, a timber frame raft with stilt supports. Her blog is entitled – Tighnanaeun – Tiny House in the Woods.

If you do visit you will see their own house construction, the lovely ‘open minded Mum’ Mrs N chose something a little different to theirs and has bought our Watford log cabin and will be living in it eventually. Until then as she tells me;

‘I am away at the moment working, but I can’t wait to get back and settle in’

‘The interior is going to be a bit of an Aladdin’s cave for the first while with sheep feed, tools and old ladies in it.’

Mrs N told a colleague of mine her son was a little jealous as his build is still going on whereas our Vlieland log cabin took two days. ‘The main bulk of the build was myself, our 74 year old amazing neighbour and my 20 year old son, it was good. Easy.’

These are the amazing pictures this lovely lady sent me following her build and I’m really looking forward to seeing the final pictures I’m promised when it’s all completely finished.

Log cabin package on the croft. I can only assume they must have had a tractor as there is no way our forklift could get here.

Log cabin package on the croft. I can only assume they must have had a tractor as there is no way our forklift could get there.

Marking out the base area for the log cabin timber frame base.

Marking out the base area for the log cabin timber frame base.

Amazing use of telegraph poles as a base support.

Amazing use of telegraph poles as a base support.

The perfect way of building a timber frame base. The first foundation logs have been added.

The perfect way of building a timber frame base. The first layer of wall logs have been added. If you are building a timber frame base this is the way to do it. Start with a perimeter frame. Support the main wall logs and then build from there incorporating your floor joists. One slight thing they are using the foundation beams we supply, this is not needed as the base is already accomplishing that task which is to protect the first log layer from contact with the ground.

The decking area has been laid and you can see how well built the base is. The floor joists are incorporated within the build.

The decking area has been laid and you can see how well built the base is. The floor joists are incorporated within the build. I cannot quite make it out but I assume they are using joist hangers which is the best way for the internal framing.

Starting to take shape! Notice how the walls at the front are bowing out, this often causes a panic for some builders but these guys, they know it will all pull together once the top log is in.

Starting to take shape! Notice how the walls at the front are bowing out, this often causes a panic for some builders but not these guys, they know it will all pull together once the top log is in.

Apexes are in and now the purlins to go in which is often the trickiest part to do.

Apexes are in and now the purlins are to go in which is often the trickiest part to do of any build.

Purlins are in and the excitement has ended, now it's all the boring bits, adding the roof boards and finishing can take as long as the main build. I think they will have another day on top of this build until it is finished.

Purlins are in and the excitement has ended, now it’s all the boring bits, adding the roof boards and finishing can take as long as the main build. I think they will have another day on top of this build until it is finished.

Roof boards are on and the insulation is ready to go on the roof. I'd love to know if this was the end of the first day or some point the following day.

Roof boards are on and the insulation boards are ready to go on the roof. I’d love to know if this was the end of the first day or some point the following day.

The completed build and just look at that view. I've installed cabin in some grotty places but just look at that - amazing.

The completed build and just look at that view. I’ve installed cabins in some grotty places but just look at that – amazing – I think I’d have put it up for free had I known I’d be working in that environment!

The completed build in two days and good enough to live in. A 58mm log cabin is a proper building with so many applications it can be put to.

The completed build in two days and good enough to live in. A 58mm log cabin is a proper building with so many applications it can be put to. This has been an amazing build and a real pleasure for me to see and enjoy.

I’m incredibly jealous, something like this is a dream of mine. It makes my small field with my Shepherd Hut on look very inadequate but at least while I’m there I have some nature and quiet around me, one day though ….. 64 acres … WOW!

I would happily live in a 58mm log cabin, if it is correctly insulated in the roof and floor they are very cozy and are a ‘proper’ building as I refer to them.

Timber frame bases are my most favourite bases from all the bases you could use in a log cabin, they don’t impact on the environment, you don’t need costly concrete, it’s temporary and will never allow your building to rot. Plus they’re exciting or have I just revealed I’m a little sad getting excited over a timber frame base for log cabins?

You can also see another example of a timber frame base with Mr Teagues Edeleweiss log cabin project another one I got quite excited about …. oh dear .. there’s no hope!

I wish Mrs N and her family all the best in their croft and shared resources, I am incredibly jealous and one day I hope to live somewhere similar.

To finish, Just look at their toilet!

bog-hut

Affectionately know as the ‘Treebog’ – I love it! Another passion of mine …. um …composting toilets … everyone should have one!

Please visit their blog and you will see some wonderful pictures: Tighnanaeun – Tiny House in the Woods

Nearly finished …. but not quite….

My colleague had a conversation about wood burners, stoves etc with Mrs N and I thought I would add Mrs N’s kind advice in case you are interested. I’m looking for one for my hut so I will be looking into them myself:

‘This is the woodburning cooker, with oven I was telling Jos about. Son in law ( a chef) and daughter have used it a lot, roasts, casseroles, soups, fry ups and it heats their house brilliantly, 3 kW. I just thought that  this type of cooker has been used in Sweden since 1800’s, a guy on this rig remembers his mum cooking on one in Norway when he was young. Surely it is ideal for ‘us’ cabin builders…

https://vedspis.se/en/ovens/Wood+Burning+Ranges/  the help from the company in Sweden was great.’

Really finally … if you have an interesting build or even just a normal build please send me pictures of it and I will write about it based on your comments and story, we’ll shower you with presents, gifts and thank you’s. Mrs N has some nice presents heading her way which I hope she will be very pleased with.

More timber framed posts:

You may be also interested in other customers buildings posts and thoughts:

 

Base requirements for Log Cabins

Log cabins are not built like a shed,  at least the good ones aren’t.

What I mean by this is;

Sheds:  When a shed is installed the floor is placed down first, the walls go on top of it and the build is continued.

Log Cabins:  With the majority of log cabins, the cabin is first built and the floor goes in afterwards and sits within the cabin and is not an integral part of it.  The floor system is known as a ‘floating floor’ and should not actually touch the cabin walls although the floor joists may be and more often than not are attached to the log cabin foundation beams.

A normal Shed is built on top of a floor with joists underneath it

A log cabin is built around a perimeter foundation beam, the floor joist and floor will go in after the cabin has been built.

Foundation Beam.

All our cabins are built around the perimeter of a base and it is prefered that it is built on a foundation beam.

As standard we supply 70mm x 44mm tanalised beams.  These are supplied to go around the perimeter of the building and to sit between the first log and the base.

Using these gives your first layer of logs protection from sitting directly in any water.  If you would like something a little better we also have, as an option, profiled foundation beams.

These are supplied with all our cabins and go between the base and the first log around the perimeter of the cabin
Tanlised foundation beams.  These are supplied with all our cabins and go in between the base and the first log around the perimeter of the cabin.
These beams are profiled to allow any water to be flushed away from the first log. Available in tanalised and hardwood
These beams are profiled to allow any water to be flushed away from the first log. Available in tanalised and hardwood
The same as the ones above but these ones are made of a composite material and will never, ever rot
The same as the ones above but these ones are made of a composite material and will never, ever rot
The foundation beam runs around the perimeter and underneath the first log and acts as sacrificial timber and ensures the first log is kept away from any wet

Perimeter

Understanding the above you will realise that all of the weight is on the perimeter of the cabin.

When constructing a base consideration should be given to this.  Sadly I’ve been to several fits where the centre of the base is great but the edges are all chipped and drooping where the shuttering has been removed as all the concentration had been placed on the majority of the base with an eye to shed building.

The greatest strength for a log cabin base should be within the perimeter as this is where all the weight is.

Level

Our Log Cabins are extremely precise things, the best machinery is used to mill the timber and as such there is little tolerance. They are designed for each log to sit directly on top of one another and are interlocked in the corners via corner connection and the tongue and groove connection along the log.  They are designed to withstand vertical forces, they are not however designed to withstand any lateral forces.

It is quite often tempting for a landscaping / building company, as they are used to doing with patios, to add a slight incline to the base to help with drainage.  They tend to do this as a matter of course without consultation and are really chuffed to tell you that you have a 2 degree incline!

This is really not very helpful as in effect you’ll be building your cabin on a slope and subjecting it to the lateral forces simply from gravity.  A cabin is really not up to handling gravity and the subsequent sideways force it puts upon it when on any sort of slope.

The end result will be a buckling and warping building and most certainly it will feature split and strained logs over time and of course the inevitable tears as you see your lovely building disintegrate over time.

The biggest thing though about an unlevel base is that it makes it bloomin’ hard to put the thing together, fully expect all sorts of problems with a wonky base:

  • The logs won’t seat properly.
  • The windows or doors will be on the huh.
  • The apex will not sit flush with the upper wall leaving a gap which you will then have to trim to look anything, either with a planer or bits of wood stuck on it.
  • The roof boards will not go on straight and there will be an incline in them which looks terrible and you will always notice it.
  • Long term problems with warping, twisting, straining, cracking and splitting.
  • You’ll be on the phone to me immediately during installation as it’s not going together  or in about 3 months time when it’s falling apart.  I’ll pop out and look at your base and tut a lot, we’ll end up arguing and you won’t even offer me a cup of tea!

What if the base isn’t level?

Sometimes we have to use what we’re given or that which is already laid and there’s not often a great deal we can do about it.  Trying to add a screed to a concrete base to get it level rarely works and will simply fall away as pressure is put on it.

If the base is out we have to do something about it before the cabin can be built, either it’s demolished and started again or another solution needs to be found.

When I fit, which isn’t often these days I carry a box of ‘slithers’ of pressure treated timber in my van of various lengths and depths. Using these I could often overcome any deviation by adding them to the foundation beam and ‘chocking’ where necessary.

However, if you are going to chock a cabin up for goodness sake make sure it is supporting the whole length and not just a corner.

Here’s an example:

poor-log-cabin-support

This was a log cabin ‘gone bad’ I recently visited to help sort the poor thing out.  Its a bit of a long story but the customer had some particularly shoddy builders in to build it for them who neither cared nor had a clue what they were doing and this was a substantial and very expensive log cabin.

The above image shows their version of chocking up the corner to make up the deficit in the unlevel base.  This piece of plywood doubled up was supporting the corner of a huge 70mm log cabin.  Not only had all the logs sagged across a 1m stretch the corner joints were also badly damaged and did not fit as it was still badly out of level.  The apex was also ripped apart and don’t even get me started on the purlins.  But if it had worked –  the plywood would have rot within a year and the whole thing would drop and destroy the cabin anyway!

Here’s how it’s best done:

good-support-logs

I took the building down for the customer and reassembled it correctly and this is how I chocked the fault in the base, notice I am using tanalised timber and that it is being supported along it’s length and kept properly level.

So, with a trusty box of slithers of tanalised timber most unlevel areas can be overcome just make sure you have several depths available to you.

Please though, use timber that isn’t going to rot in five minutes and make sure the foundation beam is supported throughout its length and, importantly, make sure the building is completely level in both planes regardless what you do.

Footprint

All Tuindeco log cabin measurement are taken from one end of the log to the other, so a 3.0m wide log cabin is exactly that, from the outer edge of the log to the outer edge is exactly 3.0m.  The base doesn’t specifically need to be to this measurement as all the logs have a crossover connection, this is generally 100mm or less depending on the size of the cabin (please ask us for your particular building).

So, for instance the base actually needed for a 3.00m wide log cabin is:

  • Length of log – 3000mm or 3.00m
  • Crossover – 100mm

Log – (crossover x2) = 2800mm or 2.80m

In this example we could make our base at exactly 2.80m wide and the log cabin will fit on it exactly.  Be careful though, there maybe a wiggle in the shuttering or somebody is not as exact as they could be, there’s no room for error when doing it exactly to the footprint so it might be wise to add a centimeter or two either side just in case.

If it can be done though I think it looks far nicer, it also has the advantage that when it rains water does not hit the base and fly up and make your lower wall of your smart, new log cabin all dirty and mucky.

Water and mud splashing up on the logs because the base is bigger than than the footprint

Another good idea when making the base to the size of the footprint is to then add a French Drain, this looks really nice and also absorbs the water, stopping it splashing up and also removes the need for guttering.  The other advantage is the loose stones can then cover any of the concrete you don’t want to see.  Apologies this isn’t a log cabin but I’m sure you get the gist:

French Drains are very useful around a log cabin base

Log Cabin Base Requirement Summary

A base can be pretty much made out of anything and we’ll get onto that in a moment but any base provided for any log cabin has to follow this criteria:

  • Consideration should be given to the majority of the weight being placed on the perimeter of the cabin.
  • Consideration should be given to the weight of the cabin, a 19mm is obviously considerably different to a 70mm.
  • It should be 100% level in every direction.
  • Ideally it should be square.
  • Ideally to just over the footprint size of the cabin.

Type of Bases

I hope with the above waffle I’ve given you a little idea what we’re ideally looking for in a base for your new and sparkly log cabin.  I’m not going to go into how to build a base as I’m not a builder or landscaper, nor would I want to be as it looks like jolly hard work.  I will however give you a few examples of what can be done and used.

Concrete

A base of concrete can be done in a number of ways.  Generally it can be done with simple timber shuttering.  The average base will be about 80 – 100mm deep.

Simple concrete base with timber shuttering
Simple concrete base with timber shuttering

Concrete Blockwork

We can also get a little more complicated with a block work supporting wall and then filling with concrete, perhaps reserved for the bigger buildings that needs a little more weight supporting structure around the perimeter.

If you’ve got a large building your landscaper or builder may advise steel reinforcing within the base itself, remember though not to forget the perimeter.

Steel reinforcing within the concrete base
Steel reinforcing within the concrete base

For advice on mix ratios, strength of concrete etc I’m afraid I’m not the one to ask, there’s lots of advice across the net and it’s probably best you sought that information elsewhere.

However! If i’m pressed to offer my very basic advice from experience use a mix of one bucket of portland cement to five buckets of ‘all in 20mm’ ballast gravel and add the water slowly, don’t make it too wet though, it needs to be a workable fluid, keep mixing until it’s uniform in colour.

As a rule of thumb calculate the volume you require (LxDxB) and add one third.

Creating the base is pretty straight forward, use timber board as shuttering to guide the edges, mark out the area and use a tape or string corner to corner to ensure it is straight.

Level the shuttering with a spirit level and pour your concrete.   Keep working it across the surface with a board until it is level with the top of the shuttering boards.  Allow it to set for three or four days and et voila your base is formed.

Alternatively; ask someone who know’s what they’re doing.  The above concrete method sounds good in principle but I’ve never managed to get it right and still had a few undulations in it, depressions are fine, hills aren’t so good!

Slabs

This probably doesn’t even need an explanation as it’s very cost effective and pretty simple to lay.  Again like concrete follow the base criteria I mentioned.  Normally a 70mm layer of dry sand and cement is sufficient, tamped down until level with the slabs then levelled on top of it.  A quick method and probably the cheapest and can work for most of the cabins we sell.

This I can get right and is pretty straightforward, just make sure it’s all level.

I have in the past tried the various other ‘eco’ slab bases but I could never really get on with them, they were more expensive than a simple concrete slab and still required the same amount of levelling, I still remain to be convinced of their real benefit and hope to be one day.

Timber Frame

This is by far my favourite method of laying a base, of course it’s not the best way I just enjoy doing it as there are so many permutations and challenges.

It’s using a timber frame supported by stilts, or pads or simply paving slabs positioned at intervals.  I find it a good environmentally friendly solution and great for areas where concrete is just not possible or when there are steep inclines to overcome.

There’s no hard or fast ways of doing it so I’ll simply give you a few examples for ideas:

A Stilt base, great for air circulation and to be flash you can say you are adopting the principles of Walter Segal

Example-frame-base-for-log-cabins

Timber frame on a bed of shingles

Timber Frames

The perfect way of building a timber frame base. The first foundation logs have been added.

The perfect way of building a timber frame base. The first foundation logs have been added.

Timber Frame Base

Square and level is the key!

What I love about a timber frame base is that:

  • It can be moved.
  • It’s truly a temporary structure which is great in certain circumstances.
  • It allows air flow and therefore the timber will never rot even if it’s not treated.
  • It’s a cheap solution in inaccessible areas for concrete.
  • Cheap overall.
  • If subsidence occurs you can simply jack up the area concerned and re-pin.
  • A good system when flooding occurs naturally and does not affect it’s environment.

To make leveling the base we do have a nice product. It’s not a bad price either and you can level between 30mm and 140mm using a combination of two units:

Very useful pads for easily supporting and leveling a timber frame base for your log cabin

Very useful pads for easily supporting and leveling a timber frame base for your log cabin

Please also see a recent post about a customer’s building for more examples of a timber frame base for log cabins:

Log Cabin Base Construction Summary

I’ve missed out loads of other ways, one of them being a brick or block plinth such as this:

Block Plinth base

There’s also systems on the market such as this:

Jackpad system of supporting a timber base frame

Pad supporting timber frame on a log cabin

There is truly a myriad of systems out there to form a base for your log cabin, much of it is down simply to cost and then personal preference and of course convenience, more than likely I’ve confused you more but no matter which method you pick:

If you want to be able to install your log cabin easily and then have it last for year and years then the base must be to the following criteria;

  • Give consideration that the majority of the weight is being placed on the perimeter of the cabin.
  • Give consideration to the weight of the cabin, a 50mm base is not going to cut it for a a huge 70mm beast of a building.
  • It should be 100% level in every direction and this is THE most important factor
  • Ideally it should be square.
  • Ideally to just over the footprint size of the cabin.

Just one last thing for you to consider and a bit of advice, if you’re opting for a concrete or paving slab base think about adding a damp proof membrane either within it or on top of it, this will then stop any damp coming up and impacting on your log cabin during the winter months.

I hope this has helped, feel free to comment or contact me if i can help further especially with the timber frame bases as I really enjoy these and love seeing them used in tricky situations.  For advice on the slabs and concrete bases it might be better to ask a builder!

UPDATE: Here’s various diagrams I have since added to other posts that may also benefit the reader of this post:

Advice on using a Damp proof course in your base.

Advice on using a Damp proof course in your base.

The base configuration when using our profiled foundation beams.

The base configuration when using our profiled foundation beams.

Insulation in the floor

Insulation in the floor and foundation beams.

Decking – the usual method

I’ve been asked a lot recently about our garden decking and especially how it is installed and on what sort of base, so I thought a short guide maybe helpful to our customers.  Of course it’s also a plug about our products, our composite decking is proving very popular as are our decking tiles and decking boards.  Interestingly sales  for the composite decking is increasing month on month

Composite decking

Composite decking

As a quick guide I suggest the following, of course there are lots of ways of accomplishing the same thing but this, I hope, is a good guide or at least gives you a few pointers.

Planning

Like any project, planning is the most important part, it shouldn’t be overlooked, what’s the old saying?  The five ‘P’s’:  Planning Prevents Pi – –  Poor Performance!

So, first make a rough drawing of your design, laying out pieces of wood to mark the edge of the planned decking always helps me to visualise how it will look.  Decking board at right angles helps to draw your eye into the house, board’s parallel show off the width of the decking.

It’s a good idea to make a scale drawing and also add the house walls, openings, obstacles etc.  If you’re attaching the deck to your house always make sure that the attachment point is 150mm below the damp proof course.  Make sure as well, you allow access to inspection covers and importantly don’t block air vents.

Measuring

Using your scale drawing calculate the area of the deck.  Divide the area of the deck by the size of the decking tiles you are using or the timber / composite decking planks.  Remember you will have to include spaces for expansion and drainage between planks, I tend to use 5mm as a guide.

If you need help calculating what is required please do contact us.

Ground Work

Decking is usually built on a framework supported by concrete footings.  It can either be simply placed at ‘ground level’ or if needed ‘raised’ using uprights.

First it’s a good idea to use pegs and string to set out the deck perimeter.  Clear all turf and vegetation and firm the ground if needed.  It’s a really good idea to lay weed inhibiting membrane down on the area at this point to stop any nasties coming through.

Decking Frame

The framework should be put on concrete foundations.  You could lay concrete for this but slabs are a lot easier.  Slabs would normally be placed in a grid pattern about 1400mm apart to allow for adequate support for the joists.  If you have bad drainage or poor soil condition consider using poured concrete in holes of at least 300mm square.  Use a spirit level and try to make sure the deck slopes (away from the house) roughly 10mm for every meter.

Create the outer frame of the deck with pressure treated, tanalised timber.  150mm x 50mm is ideal.  Where the timber touches the ground use a damp proof course membrane.  In our ‘ground level’ method these joists will simply be placed on the ground being supported by the concrete grid.  For the ‘raised’ method these will be supported by uprights, I recommend 90 – 100mm sq tanalised timber.

With the frame in place use at least 100mm screws and wood glue to fix it together.  If the decking is being attached to the house make sure you add plenty of spacers to allow for a drainage gap.  Stainless steel washers are excellent for this.  Next you will infill the outer frame with joists spaced at 400mm intervals.  These should be at right angles to the finished decking tiles or boards.  You could use off cuts of timber to create noggins in between the joists for extra strength.

Laying the Decking

Once your framework is complete and totally rigid you can start laying your decking boards or tiles.  Lay about 6 boards at a time, I have already mentioned an expansion gap and to accomplish this evenly I tend to use a decking screw as a spacer (remove after fixing).

A few notes on fixing your decking boards:

  • Always use stainless steel or galvanised screws, there’s nothing worse than seeing rusty screw heads and stained decking boards.
  • Always pre-drill your screw holes, without this you run a risk of splitting the timber.
  • Screw the end of the boards first and then to every joist.
  • If the decking boards are wider than the deck you must make sure you stagger the boards and that joints are over a joist.

Raised Decks

Raised decks are slightly trickier and need a little bit more thought.  As I mentioned you will be using uprights of about 100mm square.  These will be held in place using metal supports of either a bolt in style or an adjustable concreted anchor.

Bolt down post anchors

Bolt down post anchors

 

Concrete anchor for posts

Concrete anchor for posts

 

The frame is constructed as above but will be utilising joist hangers for added strength.

If the deck is over 60cm in height we strongly recommend a rail to prevent a nasty fall.

Also, any cut timber or drill holes would benefit from a timber treatment

I hope this has been helpful.  If you need any help or advice with your decking project please contact us