Structural Insulated Panels (or SIPs) are a surprisingly accessible and straightforward way for the lay person to build small buildings. Here are some of the things I wish I’d known before I got started on the construction of my workshop.
I took half a day off today in the hope of getting the floor down, but only got about 3 hours work done because of intermittent torrential rain and howling gales. Most of this time was spent frantically covering and uncovering various panels to prevent them getting too wet. Still it was enough time to learn a few lessons about building with SIPs.
1. it is not really advisable to try and do a SIP building on your own.
I found I could just about manhandle the medium sized panels (2.4Mx1.2M / 4’ x 8’) with the help of a skateboard to push them around over hard and flat surfaces. When I got to my back garden (picture the battle of the Somme) the skateboard was no good. I found that although I could lift the panels off the ground, they are a bit too wide for my short arms to carry for any distance, so much dragging and tipping was needed.
I think I can manage standing up the walls on my own, but the 5m (15ft) roof panels are going to be a struggle even with two people. Luckily for me, my younger brother is visiting and I will be availing him of his kind offer to help, should it ever stop raining. Which leads me on to my next tip.
lesson learned: get someone to help you with the heavy lifting.
2. Do not let your panels get wet
The tarpaulin I had covering my SIPS became partially unhitched during one of the many recent storms we’ve had and a couple of the panels got a good soaking. Although to the naked eye the panels did not appear to have swollen significantly, you can certainly tell when you try to insert the connecting timbers (see below)
lesson learned: an ideal place to build with Sips would be e.g Arizona.
3. Own more than one tarpaulin
Now I have my panels in two locations I am having to resort to covering some of them with polythene which, although reasonably sturdy, is unlikely to sustain the 30mph gale blowing outside. I have also spent the last 20 minutes creating increasingly heath Robinson devices to stop my tarpaulin blowing away.
lesson learned: get 2 tarpaulins (large – at least 8m wide) and then take the time to secure them properly BEFORE the wind gets up.
4. Prefit the joining timbers
There are lots of way to join SIPS together, and the firm I used supply a combination of timber joists (structural for main joints in floors and roof) and mini-sips. the mini-sips in particular are a very tight fit, which lead to a lot of banging around to get them to fit.
I am hoping the floor is the worst area to do since the weight of the panels works against you by pressing on the connecting timbers and also on to the sub-frame, which adds up to a lot of resistance. I managed to get them together in the end but had to leave a 4mm gap on one stubborn panel – I am not happy about that, but you only have so long before the glue goes off and in this case I had to admit defeat.
lesson learned: for very tight fitting joining pieces take the time to chamfer the leading edges and plane down as needed – it will save time in the long run. You can also make a panel basher to help persuade the pieces together without doing too much damage to the OSB boards. See pic below!
5. wear gloves
The panels are nailed and glued using a foaming glue, which is not at all tacky to touch, but goes off to form a hard and airtight bond between the touching surface. This includes your hands (see below). I will be with my new look for some time, since all the normal tricks (salt, olive oil and petroleum jelly) have had no effect.
lesson learned: wear gloves.