The Extension Part 7: Setting out the roof wall plates

The Extension project is now up to plate level so it’s time for Pythagoras’ theorem.

“Plate level is the timber plate which is going to hold the roof structure including the roof joists, hips and roof rafters.

“When you put this on you need to spend a lot of time getting this right because carpenters curse bricklayers like mad if they’ve bedded the plate on and it’s wrong and some carpenters even prefer to put the plate on themselves.

“Luckily Mark, our bricklayer, is very diligent and he bedded it the old fashioned way. It comes off the existing plate of the house and we used a laser level to ensure that it is level all the way round and we’ve also checked that the whole thing is square which is also really important.”

3-4-5- method

“You can do that using a folding square but an alternative way to check the plates are square which can be useful on larger roofs is to use the 3-4-5 method.

“Take any 3 measurement such as 30 inches from the corner down one side, then measure 40 inches down the other side and the distance between the two points will be 50 inches if the corner is 90 degrees.”

About Roger Bisby

Roger Bisby
Roger Bisby is an English television presenter and journalist, known for his expertise in the British building industry.

One comment

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    How do you get over the problem of a roof plates overall width being 100mm wider one end to another .assuming the brickwork cannot be adjusted would you hang the plate off the brickwork 50mm each side or put on a 150mm timber plate and diminish it to 100mm giving you the same width overall on the outside and a decent bearing on the brickwork,I’m aware this will close the cavity slightly or is there another way..?.

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