Dealing with Expansion And Contraction

Expansion and contraction as things heat up and cool down, is something that every child learns at school. It’s one of those things that I mostly believed about because it was taught in school, but nothing I really thought would make much of an impact in my life. Well, I was wrong!

So, here we are, living in house made out of giant metal boxes. Expansion and contraction is a thing that we have visibly seen as the weather changes through the seasons and even day by day. Kevin knew it would be a problem, and we would have to run many experiments to see what survived this phenomenon the best, especially in regards to the joints in the interior cladding boards.

Problems that Expansion and Contraction Have Caused Us

Here are some things that have caused us problems:

• Joints in cladding boards are where the problems lie, even behind tiles. We have had a few tiles develop hairline fractures exactly where the board edges are, especially on softer type tiles.
• Some areas of grouting cracked loose. The worst areas were in corners.
• On some of our interior walls, we tried OSB boards for the cladding. We used plaster skim to hide the joints. Over that we hung wallpaper. The wallpaper worked very well, but you can still see where the joins in the boards are, if you look carefully. The paper is having to flex around the seam. The other problem is that the resin from the knots in the wood has bled through in some areas, marking the wall paper.
• We then tried marine plywood as our interior cladding, and covered the boards with paint and hessian. This worked exceptionally well, but we still had the problem of trying to hide the joins in the hessian.
• Lastly, we’ve tried chipboard (USA = particle board) for the interior cladding and filled the seams with paintable acrylic sealant (caulking). This particular area of the house is the most affected by the sunshine as it is on the North side. It didn’t work.

We’re not too worried about the cracks showing through, as we knew this house is a bit of an experiment. It was always likely that we would have to redo a few things, or try something else a few years in the future when it becomes time for maintenance. However, we have learnt a thing or two:

Things We Have Learnt

• Ensure that there are no joins behind tiles in critcal areas, such as in the shower. There’s no getting away from joins in the corner of the shower. In that area, behind the tiles, Kevin securely glued in aluminium angles, against the cladding. So far, it’s working!
• Create expansion joints in the grout by using silicone instead of traditional grout. We used silicon in all the corners of the bathrooms; both horizontal and vertical. We used standard grout on flat surfaces. Silicone caulking is available in many colours so we were able to match it up to the grout and it’s difficult to tell what’s grout and what’s silicone.
• If you want to try the wallpaper idea in your own project, we suggest using darker colours that will hide any marks that bleed through. Alternatively, you could try a plastic based wallpaper.
• The hessian and paint trick worked fantastically well, but worked out a little pricier than we were hoping. We had to soak the hessian in paint to get it to stick to the walls properly and found ourselves reglueing sections. Using cheap paint for the sticking helped a bit, and then we painted over everything with a good quality paint once it was secure and dry. We used fabric strapping for the joins. Another option you could try would be glueing the hessian in place horizontally (we glued it vertically) and placing a dado rail over the join in the hessian.

We’d love to hear how you deal with expansion and contraction if this has ever been an issue in one of your projects.