“Which Log Cabin Foundation Types are Best for You?”
There are numerous log cabin foundation types around, so we want to help you to know what the differences are between alternative methods. Finding the best one for you will depend on specific site factors. Soil type, proximity to trees, ground levels and access for digging equipment, can all affect your decision. What you should never do is cheap out on your foundations and put in something which is not strong enough, or will affect your logs in time. Again use a foundation which relates to your overall project. So if you are doing a large house, you need to spend much more attention than if you were doing a small garden cabin for example. Always follow local building regulations or codes, (where these apply) and consult with structural engineers to get proper calculations undertaken.You may need to dig a trial hole, or do a soil bore to investigate your soil conditions properly.
Which type of Log Cabin Foundation?
Please note all drawings on this page are for illustration purposes only! Always get professional advice from a qualified engineer before undertaking any foundations.
A perimeter foundation is one of the log cabin foundation types we used quite a bit in the UK. This is basically an external wall which has a step down to the inside which allows floor joist to be located here. Depending on the width of your log cabin and the size of your floor joists, you may well need an internal support wall or walls, to support the joists at certain intervals. This design is an open solum type, which means the air can circulate under the floor. This is achieved by fitting air bricks into the external walls just below joist level. This stops the build up of moisture, which is good news for the timber. A thick polythene sheet covered with deep pea gravel, will stop any vegetation growing underneath the building.
Log cabin foundation types - Perimeter
A strip foundation is basically a concrete foundation, which is usually deep enough to combat any frost or soil heave issues. On top of this brick or blocks walls are formed, to the desired height above ground level (should be minimum of 150mm or 6 inches). Hardcore is then compacted on the inside, on which a concrete floor is cast. It is a relatively straight forward method, but you will need to go reasonably deep.
Log cabin foundation types - Strip
This foundation type usually means you don’t have to go so deep, as it is stronger (being made out one piece of concrete). It can also be a good method if tree roots are an issue, as it is strong and the concrete will resist the root trying to go through. It does require a lot of concrete, but less bricks and block work are required.
Log cabin foundation types - Raft
Concrete pad foundations
A simple and popular method of foundation, which is widely used for houses. Involves more concrete than strips foundations, but less depth which saves on the digging end. Reinforcement may be needed in some cases, but as ever check with a qualified engineer, who can specify these sort of details.
Log cabin foundation types - Concrete pad
These are basically a structure which comes out of the ground to support the building at a specific point. Many of these are built at strategic load bearing locations, which when combined together, they support the whole structure. Normally these would be made from bricks or blocks. These could be left exposed or rendered afterwards. Stone can also be used (although this is much more expensive). I have even seen old wooden telegraph poles cut down and put in the ground. However I would recommend avoiding timber at or below ground level, due to potential wood rot in the future.
Log cabin foundation types - Piers
More recently there have been some clever modern alternatives to conventional foundations. One I particularly like was developed by a company called Swift in the UK. It basically consists of an adjustable pre-formed kit which is installed at designated load points. It requires little digging or other materials and could be done by most able bodied people. The beauty of it is, cheap overall cost and adjustability to get your levels right.
Log cabin foundation types - Modern alternatives
Take a look in more detail at Swift foundations
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