8. Side Walls
Unless your building is square, these are smaller and easier to build and lift than the front and back walls. However, depending on how you build them they can be a little tricky.
My garden room’s front wall is higher than the back wall. That means my side walls have to slope down from front to back (raked). The point of all this is to create the gradient of the finished roof for water runoff at this stage BUT you can do it later on with furring strips on top of the roof joists and instead have all 4 walls of your garden room the same height. Arguably this is an easier option from a building perspective but there are a few downsides which swayed me towards building mine with sloping side walls.
To get a full understanding of the two options have a watch of Part 9. Roof Structure.
Alternative method for rake walls
Assuming you match what I do but don’t fancy all the angles you can build a flat-topped wall with the top plate level with your back/lower wall. Once all the walls are erected and attached together you can then add your second top plate between the front and back walls and fill in the gap with mini-studs (marked in orange in the diagram above). This way, if you make a mistake with your angled cut it will only be on a small off-cut of timber. The downside is the mini-studs are trickier to attach the flat top plate below.
Do you need headers for the side walls?
Not really! It only occurred to me later on that they weren’t necessary above the windows. The reason for this is the side walls aren’t doing much work to hold up the roof as the joists on my build are orientated front to back. So if your build is the same, you can use the same timber as your walls (2×4″ in my case) to frame above the window. This can be attached sideways through your jack studs so you can get rid of the trimmer studs and save some money there.
With four walls your build is really coming together and will feel more like a room. Keep going to get it water tight!
Task: Whether you choose flat topped or sloped walls, get them built and attach all four walls together. Take some time to adjust your bracing so all the walls are as straight as possible. We’ll keep these braces in place until the roof joists are doing the job instead.