Pent Installation Roof Advice

A little insight to how you can format the parts of our Modern log cabins

So you have built up your new log cabin up to roof height and you will come across a sight like the one below, the skeleton of a roof ready to be finished off.

Up to roof height with purlins added

I have made a quick guide which I hope proves useful, there are different methods in doing this roof style that you may prefer to use.

Firstly lets identify all the roof components that we will eventually call upon, in this case we have the two-tiered eaves boards for all four sides, squared battens and a mixture of mounting slats and blocks, sometimes the eaves boards for the longer cabins arrive in half lengths which when offered up to one another span the full required length. 

Identifying Roof Components

A good opportunity is often missed at this stage which is treatment and plenty of it as a lot of these parts become very inaccessible once you get further along, for more guidance on what treatments to use you may be interested in the following; https://www.tuin.co.uk/blog/log-cabin-treatment-again/

To begin with let us install the mounting blocks on the front and back of this particular log cabin, these provide more support for the eaves boards when you fit them, sometimes these blocks can be fitted to the sides instead, depending on the model, to fix these I am going to use a two of the 60mm screws at each point.

Starting to install the mounting blocks

Please do not think too long and hard where the mounting blocks need to be placed, as if the plans in front of you do not show a specific precise location, as the eaves boards may have arrived disassembled as shown in the second image above, just place them in a realistic fashion and copy the same for the back.

Mounting blocks also fitted to the back wall

The mounting blocks have all been fitted, so now it is time to think about making up the eaves boards, in this case we have been supplied with a narrow and a wider board, these two together make up the full eaves height, you may have seen that the plans are telling me to use the wider boards on the top, so let us do just that.

Eaves boards ready to be assembled

To join the two boards together we need to use the mounting slats supplied in the kit and identified earlier, anything can be used including spare pallet timber.
Please pilot drill these before securing them, by doing this with any wood you can be more sure that the wood will not split or crack, make sure their locations are correct, use the roof as a guide lining up the slats with the blocks already in place or take measurements.

Offering Eaves boards up to the fitted block locations to aid positioning

Screw the mounting slats all onto one side of the boards, I used 30mm screws which worked nicely.

Screws sent though the mounting slats into the eaves boards

Mounting slats lining up with mounting blocks and overhanging the wall logs/purlins.

Mounting slats lining up with mounting blocks

Now we have all the eaves boards made up as well as all mounting blocks and slats fitted, we then need to think about how we want the chosen roof material to be formatted.Roofing Felt, Easy Roofing or EPDM

Felt, Easy roofing and EPDM Roofing for our pent roofed log cabins

Fitting roofing felt, Our aim is to fold this under the roof edge on all four sides of the roof securing it into place using the supplied battens or sourced trims.

Fitting Easy Roofing ( ERM ) this is an easier solution to roofing felt and requires no nails as its all self adhesive, A heat gun in the colder months of the year is suggested to enhance the overlaps

Fitting EPDM now we save the best until last! The Epdm rubber roof, supplied with a spray adhesive and laid straight onto a “clean dust free roof”, like with the easy roof you would dish this up on the inside faces of the eaves boards on all four sides or just the front three

FELT ROOFING FIRST

We do have a video showing how felt in general is laid which for the basic principle is important as well as our very detailed online installation manual for pretty much everything you would need to know about getting the cabin constructed from the ground up; https://www.tuin.co.uk/blog/tuin-tuindeco-log-cabins-instruction-manual/

but more specifically here for a pent roofs which we hope helps further.

Assuming it is felt that we are fitting today we need to get the roof boards on before anything else, However what we like to suggest at this stage is to temporally tac your front eaves on first as this then gives you a line to offer them all up against knowing they will be correct.

Eaves boards fixed to the blocks ready for the roof boards

You may find that the mounting slats obstruct some of the roof boards from sitting flush so I am trimming them down, or I could have trimmed the relevant roof boards instead to slot around them.

Cutting the mounting slats so the roof boards fit flush, The roof boards could be trimmed instead where required

With the slats trimmed the roof boards sit flush against the inside face

When you go to fit the last roof board you nearly always need to rip it down to allow it to sit flush with the ends of the purlin(s)

Remember to use two nails or screws per board at every junction as the roof boards are key to strengthening the whole building, in the summer leave a 2mm gap
in-between each board whereas in the winter you close them up as tight as possible.

After that you can then remove the front eaves board as its time to fit the felt.

As mentioned, we really want to get the felt wrapped round the ends of the roof boards and under, most cabins come with battens to attach the felt under the boards, in this instance I have been supplied with the two long lengths as shown in a previous picture, I will use these and any other spare pallet timber to secure the felt if needed.

An example of how to finish the roofing felt around the ends of the roof boards

Another example showing how to overcome obstructions

You will at points have to work your way around the mounting blocks, purlins or wall logs, you could remove the blocks temporally while the felt is fitted. you can also leave the felt simply wrapped round the sides of the roof boards to avoid the obstacles but just be sure they are secured down in some way either using Felt Glue or clout nails, Ideally both.

After the felt is fully installed you can then fit all your eaves boards around all sides, the natural gap at the back is there to allow the water to drain off the roof

Expect a gap at the back of the roof, This is for drainage

EPDM or ERM Rubber Roofing

For more specific guidance on the actual installation of the rubber itself, Please visit the following for support and advice

https://www.tuin.co.uk/Easy-Roofing-Membrane.html

EPDM on LOG CABINS roofs.

For this cabin we opted for the Easy roofing as it is the best with no overlaps, the same fitting aid also applies for the Easy roofing, for these rubber options I am going to dish the roofing up on the front three sides then wrap it around the back to allow the run off.

After the initial stage of fixing all mounting blocks onto the cabin I am going to go ahead and fix all four completed eaves boards onto the sides of the roof.

A close up of a corner, Mounting slats cut and uncut as preferred

An extra pair of hands is useful for this part, but you could use clamps if you have some large enough. I screwed through the outside fascia of the eaves boards through the mounting slat into the mounting block with two 70mm screws at each point.

Eaves boards fitted at the back, Note they sit higher than those at the front due to the roof pitch

All eaves boards in place and ready for roof boards followed by the EPDM roofing

With them all fitted to the perimeter of the roof I’m ready to fit the roof boards following the same process as we did for the felt part of the guide.

Dishing of the rubber roofing can be formatted in different ways, As an example you can just have the rubber coming upwards against the inside face and apply a hidden trim to cap it off, however it is best to actually wrap the rubber around the top of the eaves board and down the other side as it helps prevent any possible ingress under it, you can then cap this off as you wish.

You may like to cut the mounting slats down on the front three sides like we did for the felt approach early as this makes offering the Epdm rubber roof easier to lay on the inside face of the boards.

Roof boards start getting laid, Remember two nails per board at every junction

Examples of how the rubber roofing can be dished up

Then for the back where the natural drainage gap is we are going to wrap it around the side of the roof boards, Some fitters at this point will actually make cuts into the tops of the blocks so they can get the EPDM wrapped further around, But you can just glue and tac the roofing to the sides

Some fitters will be very clever at this stage and actually cut a channel into the tops of the mounting blocks, eventually fitting a guttering length directing the water into a downpipe, you may need to increase the wood size of the block used depending on the gutter size, you can then glue the EPDM into the inner face of the gutter instead.

With a channel cut on the back overhangs you can fit a guttering length rigged up to a downpipe

I will mention once again that the methods above do not have to be strictly followed, “like anything in this world there are always room for enhancements!. “So fill your boots ladies and gents” and have a go. Any questions please feel free to contact us for advice

EPDM on Log Cabins Roofs

For flat or sloping roofs on our Log Cabins we normally supply roofing felt but as an option we do have the far more superior roofing material of EPDM.

What is EPDM?

EPDM is a highly durable synthetic rubber roof membrane, it’s posh name is Ethylene Propylene Diene terpolyMer. It’s two main ingredients are Ethylene and Propylene which come from oil and natural gas. It’s been used on flat roofs for over 40 years. The main technical features of EPDM are:

  • Cyclical membrane fatigue resistance
  • Proven hail resistance
  • High resistance to ozone, weathering and abrasion
  • Flexibility in low temperatures
  • Superior resistance to extreme heat and fire
  • Thermal shock durability
  • Ultraviolet radiation resistance
  • High Wind Resistance

Why Use EPDM on your Log Cabin?

Roofing felt is an ideal solution for a flat or gently sloping roof but it’s life expectancy is not that high. About 5 years is a very good life span for ordinary felt. EPDM though has been known to last for thirty years without concern. For a long term economic prospect it is good value for money.

The benefits of EPDM on your log cabin roof are:

  • Cut to size for your building so no joints (except modular buildings)
  • Inert and UV stable
  • Will not crack or Perish
  • Environmentally friendly
  • Applied cold
  • Virtually maintenance free
  • Long Life Expectancy
  • Economical when compared to re-felting every few years

Installation of EPDM

There are three ways EPDM can be fitted and this includes Ballast, Mechanically Attached and Adhered.

The Adhered system is the one we will use and is the one used by many roofing companies. Basically it is glueing the membrane to the roof and is pretty easy to do.

Log Cabin Roof Variations

Before reading too much further all this article is going to do is tell you the basics on how to fit EPDM to your log cabin roof and simply put the membrane is:

  • Rolled out
  • Allowed to settle
  • Glued down
  • Trim as you wish

The trim as you wish is the bit that’s left up to you as there is no hard and fast rules for this. You can either finish as you would with roofing felt and tuck it behind your barge boards, you may want to trim it flush with the roof boards or you may want to do a little more. This is all up to your preference, requirements and skill set.

Also, bear in mind this is my own personal recommendation on how I do it, I’m sure other fitters, roofers, builders etc will have their own take on it. Some may even say I’m wrong which wouldn’t be the first time.

Roll out the EPDM on your Log Cabin Roof

Take the roll up on to the roof and undo the ends, you should find some glue inside in the form of spray cans.

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Normally hidden inside is enough cans to glue your roof down. It’s very unlikely you won’t have enough but any contact adhesive also works if you run out and need it quickly.

Three cans

Three cans were found in the depths of the roll. The EPDM is cut for your building, this membrane is 3.9m x 5.4m. Three cans was more than enough.

This is where I may differ from all the advice you see from the roofing people, they always say to unroll it, layout flat on the roof and then allow it to settle as it is.

I have done it this way and it works on a hot day but I still prefer my technically named sausage method.

Roll the full length out across the roof

Roll the full length out across the roof

fold out

Start to fold it out flat across the whole roof.

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Then start to roll it up again length ways, try to do this reasonably tightly, it does help if there is two of you and try to keep it as level as possible.

Keep rolling

Keep rolling together with your partner, keep it level and quite tight!

Saua

At the end you’ll end up with a sausage.

Allowed to settle on the Log Cabin Roof

When complete you’ll end up with a sausage sat at the start of your roof, I will always start at the highest point and work backwards.

I mentioned trimming earlier and you’ll notice where we have set the barge boards, this is just my preference, there is no right or wrong way. I wanted to give a little extra clearance for headroom below. It does not matter though how you do these.

It does help though to only start with the front ones on and add the side and rear if applicable later.

Once you’ve made your sausage, leave it for a little while on the roof and as it’s rolled so tightly a lot of the creases from storage will start to come out. The sun will also make it a little more pliable.

I’ve mentioned it already but it really helps if the sausage as been rolled level as you will use it’s edges later on to check you are rolling it out on the log cabin straight and true.

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If you end up with a wonky sausage unroll it and start again. Nothing worse than a wonky sausage!

 Glue the EPDM Down

This part of the install on your log cabin is exactly what it says, we are just glueing it down on to the roof. How you want to trim it is up to you, I may have mentioned this.

The principle is how I’m glueing it.

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This is something I do, you do not have to do this unless you want to.

As you will see from this picture I have used a bit of timber to create a slope against the barge board. You do not have to do this, you can finish it as you want, tuck it behind the board, glue it directly to it, however you wish.

I’ve done this though as I think it looks nicer, it also stops water going behind the barge board. Due to the height I raised the boards I was able to use a floor board to create the slope, if I had less of a height I might use a trim from skirting or roof boards or even a packing piece laying around. There is no hard and fast rules on this other than it needs to be glued down.

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I now shuffle my sausage forward and align the edge to where I finally want it to finish.

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Give the cans a good shake, I think they advise two or three minutes of vigorous shaking, I can’t remember but give them a good shake for a while.

Start to glue

Once everything is aligned and the cans have had a good shake then roll the sausage back slightly

With the sausage rolled back a little you can take the front and uncover the area to be glued. Spray the glue evenly at a length of about 50cm all the way along the roof, it does start to go off pretty quickly. You don’t need to apply it really thickly, too thick and you fight against the glue itself.

Don’t spray right to the ends or right to the front at the moment.

Glue all the way along the roof

Glue all the way along the roof at about a depth of 50cm so the glue does not go off too quickly.

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Now fold the membrane forward and start to smooth out.

I’ve seen videos and instructions and professionals and all sorts of recommendations on how to smooth out the EPDM, they’re probably really good and certainly give them ago and let me know how you get on but I still prefer to use my hands and push out the bubbles of air, smoothing the membrane as I go.

Note though I haven’t glued the edges yet as I may want to still much about with this. This is particularly the case at the sides as the barge boards are still not on.

Once the first part is done, now knell on it and roll out the rest, glueing every 50cm as you go, smoothing out as much air bubbles as you can.

Once the first part is done, now knell on it and roll out the rest, glueing every 50cm as you go, smoothing out as much air bubbles as you can.

Glueing ever 50cm and then rolling out

Glueing every 50cm and then rolling out

Smooth as you go

Smooth out any air bubbles as you go, I use my hands but you may have a better idea or system or received better advice

Another 50cm and the roof is glued down and that’s as far as this advise goes on how to fit your EPDM. It’s really quite straightforward, we’re unrolling it, then glueing down, and smoothing it out.

When the main body of the roof is down you can then work on the edges and fit the barge boards and trims as you require and completing the final glueing stage in these areas.

The rest is up to you.

Trim your Log Cabin EPDM Roof as you wish

I’m often asked what is supplied as regards trims with EPDM. I answer there is nothing extra and nor does their need to be you can use this exactly as you would felt. You can though utilise offcuts and produce slopes to ensure all the water is taken away and make a really professional job of it.

You can also use capping pieces on top to make it look nice or battens to secure it fully so as not to rely wholly on the glue at that point.

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I have the slope at the front you have already seen but I also did the same at the sides and added a capping piece to make it look nice. To the side I have added a batten to sandwich the EPDM so as not to rely completely on the glue at that point (in this picture I am yet to cut the batten flush with the barge board)

dffh

Not a bad finish, most of the air bubbles came out and pretty smooth. Shame about my boot marks but they will wash off and the creases will disappear.

sfsd

This is another fitters roof on a Yorick Log Cabin, he finished everything flush and that is his preference and still works the same in producing a secure roof for many years with water draining to the rear and following the slope. Upstands are always better though and prevents any rot to trims.

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Another fitter has added a small up stand and uses a batten to fix the EPDM at the top.

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Someone else has gone to town making top trim pieces. We also sell aluminium strips that can do this for the front of the cabin.

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Or … just fold it over the top of the barge boards. This is the Yorick Log Cabin and a customer chose to do this. Nothing wrong with is at all other than perhaps aesthetics.

Summary on Fitting EPDM to your Log Cabin

In summary all we are trying to do is glue down the membrane with as little bubbles in it as we can.

We also want the roof to drain well and if you wish, it’s nice to create slight slopes all around to encourage the water to flow. This is something the flat roof boys do on your house so we may as well do it on our log cabin. You don’t need anything special apart from a few off cuts of wood which you will have when you have finished your cabin.

Some customers worry about installing EPDM  on their log cabin but it is far the quickest roofing method, it doesn’t rip, it’s quite forgiving and easy to work with unlike felt which can be a real pain especially in very hot weather. Plus in the past 17 years now I have never had to re-meet a customer to re-do his EPDM, I’ve met a few to re-felt though!

Trimming is easy but have a ponder on how you would like it to finish before you start and make sure water drains away if the roof is totally flat on your log cabin.

For our modular buildings there will be a join as each part of the building is a separate section, all you do is glue over the seam as you would the roof and as long as you are flat this is not a problem, professional flat roofers do exactly the same.

As always, if you have any questions, please let me know.