Measurements of Log Cabins

Log Cabins – The Seven Dimensions

I have known some potential customers to have some confusion when referring to measurements of log cabins and this post will help to make it clearer, also, if you are looking at other suppliers generally they will use the same ones so this may help when looking at other options as well.

Please note though I have found a couple of UK companies measure from the roof overhang so it is worth clarifying this point if you are buying elsewhere.

There are Seven measurements of log cabins that you will be interested in and these dimensions are referred to as:

  • Log
  • Interlock
  • Foot print
  • Roof
  • Canopy
  • Log Thickness
  • Internal

I am going to use the example of a 4m x 4m log cabin.`

Log Dimensions

Our dimensions refer to the fullest extent of the wall logs, for instance this will be the configuration of a listed 4m x 4m log cabin such as the >Jari 4x4m Log Cabin

4m x 4m log cabin. The log dimensions are to the furthest extent of the logs that form the main building excluding canopies or roof overhangs. This will include a veranda.

The log dimension does not include any roof overhangs or canopy dimensions. This is the measurement of the base log that forms part of the ground plan of the building, this will not include the canopy but will include the veranda if one is featured.

Corner Interlock

Due to the construction of a log cabin we must have a corner interlocking joint. This has to be set away from the end of the log and sufficiently far enough to maintain strength and aesthetics. On most occasions this is 100mm but some cabins we do make it very slightly smaller, generally with the 19mm buildings and some corner building to keep internal space to a maximum. Check the product pages for this.

For this post and to enable understanding, and as 98% of our buildings are 100mm, we will stick with this example. This is the interlock dimension:


Interlock dimension – This is the measurement from the outside of the log to the outside face of the base log which forms the footprint.

Footprint of a log cabin

This is quite important especially when you are looking at your base. This refers to the very minimum your base can be and is the measurement required to support your wall logs properly. A base can be bigger than this but never smaller. The footprint is calculated by:

Main Base Log (4000mm) – (Interlock (100mm) x 2) = Footprint

This is the footprint dimension:

Footprint dimension

Footprint dimension – this is very important as it is the minimum dimension required for your base.

Log Cabin Roof Dimensions

This is the dimension of the roof and normally when we refer to it when asked, we state the ‘roof overhang’. This is generally 200mm – 300mm to the rear and sides on most log cabins.

If this is critical to you due to close proximity of a boundary you can happily cut this down to the full og dimensions. The roof overhang is there to protect the side walls, windows and doors from ingress of the weather. This measurement should be taken into consideration when calculating insulation or roofing material needed. Do not cut this down further than the log dimension.

Please Note: One or two suppliers list this as the cabin dimension. If you do not check you may end up with a log cabin smaller than you had expected.

Log cabin roof 'overhang' dimensions.

Log cabin roof ‘overhang’ dimensions. This is the amount that the roof boards overhang at the sides and to the rear of the main log cabin wall logs.

Canopy of a Log Cabin Dimensions

The canopy is always listed with us as an extra dimension, for instance our Stian 58mm 4m x 4m log cabin is listed as 4m x 4m but does have a 1.40m canopy. This is in addition to the mentioned 4m x 4m log dimension.

The canopy measurement is an additional measurement to the main log.

The canopy measurement is an additional measurement to the main log dimension.

Log Thickness

Log cabins that we, and others offer come in a variety of thicknesses. Please see our main categories which list these thicknesses: Tuin Log Cabins A log thickness you decide upon represents its intended use, for instance in my opinion the thicknesses can be classified as:

19mm log cabins are a storage solution to replace a shed far more economically and with a higher strength and longevity than a panelled shed.

28mm log cabins are a leisure building for use as a summerhouse or to enjoy the warmer months, it is not really for all year around use without adaptation.

34mm – 45mm log cabins are more as a studio and benefits from additional strength and heavy duty usage, these can also be added to with insulation and may work out very economical with some adaptation.

58mm cabins are for offices and accommodation and start to become a serious building for all year around uses with the addition of insulation in the roof and floor

The 70mm log cabins and above are for multiple rooms, strength and insulation properties.

Log cabin wall thickness dimension

Log cabin wall thickness dimension – this is dependant on you and your requirements from you log cabin

Internal Log Cabin Dimensions

This, against the footprint dimension, is probably the most important dimension you are interested in. This represents the amount of room you have within your log cabin and is made up of the following equation in this 4m x 4m example:

Footprint = Main Base Log (4000mm) – Interlock (100mm)

Internal Dimension = Footprint – (Log thickness x 2)


Internal Dimensions = (Log – Interlock) – Thickness

This is a log cabins internal dimension:

A log cabins internal dimension

So, if we look at the following examples the internal dimensions are:

Measurements of Log Cabins Summary

As I have mentioned above, these are the measurements of log cabins, others will do the same but it is a good idea to check with your supplier if you are not buying one of our log cabins

This entry was posted in Technical - Log Cabins and Timber and tagged , , , , by Richard. Bookmark the permalink.

About Richard

This blog is my personal platform which I do enjoy. It is my own viewpoint and my own ideas. I may not be right and other installers / experts may offer a different view point or a alternative way to do something. I welcome contributions from anybody experienced to do so.

All my blog writing is MY OWN personal opinion ONLY and is NOT always the opinion of TUIN | TUINDECO as a company.

Log Cabins and Garden timber have a myriad of intricacies , I love to give away the secrets, there are a lot!

I enjoy using this blog to expose them so you know what you are buying. I love to know I am causing a few problems in the industry as it can be on occasions less than honest.

I actively encourage everyone to install their own buildings. So many times I would fit and the company I was working for would charge loads for my time, only then to be faced with the embarrassment when the customer says 'I could have done that' and YES you can without paying hundreds of Pounds!

I have over 19 years experience within the garden timber industry. I have particular expertise in garden buildings including the manufacture, design and installation from sheds to log cabins and all the way up to timber framed houses.

In my time I have been involved with virtually every manufacturer and supplier of garden buildings. I have also installed pretty much every make of Garden Building there is from ALL suppliers and manufacturers.

Prior to my career change I was a Watch Commander in the Fire Service with particular expertise in chemical incidents, training, technical design / technology / IT /Procedures / ISO Systems and road traffic accidents. I retired due to a nasty injury after 20 years service.

During my time in the Fire Service, on my days off, I was a self employed fitter for any type of garden building, I worked with most of the well known companies as a subcontractor.

I now work with Tuin | Tuindeco in the UK, supporting and advising on the vast range of products. I keep an eye out for help requests when we a supposed to be closed and can usually get back to you out of hours via email only (wife and children permitting on my days off).

In my private life I consult as an independent expert assessor for companies or private individuals when a dispute is present over their structure which results in producing an impartial report and assessment for whoever requires it. This is often higher valued than a structural engineers report born from my credentials, experience and widely recognised as an 'Expert' in the field.

I am a freelance writer for numerous companies, publications and blogs as well as an independent expert and fault finder for parts of the Industry and consumers with a particular emphasis on timber structures, both framed and of an interlocking design such as log cabins.

I produce numerous articles about timber in general, information on general timber products and specific guides when needed. I hope you enjoy and find my writing useful.

Please contribute and comment to my posts as you would like and I will try to respond as best I can.

Thank you


3 thoughts on “Measurements of Log Cabins

We'd love your comments on this.....