Battening the insidePosted: June 9, 2012
Having completed the outside of the studio we’ve turned our attention to making the inside into something that Sal might actually be able to use to work in – step 1: batten out the inside ready for electrics and insulation.
When planning this work one of the key considerations was the expansion and contraction of the outside structure – log cabin buildings aren’t dimensionally stable and expand and contract with heat and moisture. We wanted to ensure that, once built, we’d be able to finish to a good standard and it would stay that way. In an attempt to achieve this the wall battening was laid out in the following way.
- First I placed a number of treated 19mm * 38mm battens horizontally on the wall. This way they would move as the outside wall expanded and contracted vertically (the expected direction of movement). This provided an air void between the external structure and the next layer to allow air to circulate and prevent condensation.
- Over this I placed a layer of breathable membrane and sealed it all up with waterproof tape. The purpose of the membrane is to prevent water vapour from reaching the insualtion should any water make it through the external structure. As the membrane is slightly stretchy it should remain intact as the structure expands and contracts.
- Finally I build the internal battening to hold the insulation and electrics out of 38mm * 63mm CLS timber. The internal walls were built freestanding, fixed only to the floor, to allow the external structure to move past them in expansion and contraction. A 25mm gap was left between the wall and ceiling to allow for this movement – I’ll cover this in some way once I’ve fininshed the walls and ceiling.
And that’s it – pretty straightforward all things considered.
- External battening (19*38 treated): £40.00
- Internal battening (38*63 cls): £170.00
- Breathable membrane: £75.00
- Screws and Nails: £15.00
- I don’t think I put up quite enough external battening and, as a result, the air gap is likely to be compromised. In hindsight I should have gone with 400mm centres all the way up the wall, this would also have made fitting the membrane that much easier.
- And on that note I’m not sure how effective the membrane is going to be. Due to the construction of the ceiling in particular I had to make a lot of cuts and use a lot of tape. I’m pretty sure this means that the overall membrane envelope will be badly compromised so I’m not sure it was worth it.
- Buy an electric mitre saw. I didn’t, and I spent a lot of time and energy with a handsaw and regretted it. It’s not impossible to do without but I wish I’d bought one at the outset.