The Self Build Self Help Site Installing Roof Trusses
Installing Roof Trusses

The installation of roof trusses is a milestone in the build of a new house as, on completion, the house suddenly takes shape and, with the next stage of fixing the membrane, heralds the approach of "inside work" - the great antidote to the UKs often inclement weather.

This job is something that the self-builder can certainly take on but it does demand a certain know-how and requires a number of people to take part.

There are 2 main formats of roof truss - those providing for rooms in the roof and those that do not. The former use larger profile timbers and can be heavy, almost certainly requiring a crane to raise them into position. The latter are much lighter and can be manhandled into position, saving a costly crane hire.

The photo sequence below is of the lighter weight trusses but the technique is similar for both.

This page assumes that the wall plates are in place - see our pages Fixing a Wall Plate to a Block Wall.

Click on the photos for a larger view

photo of stored trusses

After unloading from the delivery lorry, store the trusses together and keep them so that they do not distort. If they are stored distorted for sometime they may take on the shape permanently - making installation a bit trickier. One rafter of each will have a mark - keep these rafters together as that is the way they have to be positioned.

photo of stored trusses

Fix one truss against one of the gable ends and hold it in place, ensuring it is plumb, with battens fixed somewhere to the scaffolding or the wall plate.

photo of stored trusses

Hoist the rest of the trusses onto the roof and temporarily secure to the first truss. Ensure they still have the markings on the same side.

In the previous 2 photos it can be seen that we have built a platform from trestles and scaffolding boards. The boards are nailed to each other and onto wood screwed to the walls at each end - it will not move! This is so that one person can help carry the trusses into position. Now, this is where you have to seriously assess the risk, as covered by the Work at Height Regulations. Have a look at the HSE guidance here.

We consider that working from the platfrom cannot be avoided and to "minimise the distance and consequences of a fall should one occur" we place boards on the joists below for the length of the platform. We have also built the platform in consideration that this is for a discrete task which usually takes less than a couple of hours. The person on the platform is also told to stay put and hold onto the last truss fixed until required to help move another. And don't use in the wet.