Rear extension roof

[Sonnypaul]

Morning all.

Currently building an extension and I'm nearly at wall plate height.
The majority of extensions I do go out 3 meters but this one is only 2500mm out from the house.

I'm using redlans 49s smooth. Min pitch 17.5.

My question is, should I pitch the roof at 17.5

Or raise the Pitch higher one course below the sill.

Or pitch the roof under the sill.

Thanks guys

 

[noseall]

Have we not had this conversation already?

Ideally you would pitch the rafter to finish a couple of courses below the window sill in order to accommodate the flashing up-stand, the tile and batten.

If this happens to shallow out the roof too much, then you need to re-think the design. Either replace the windows with less deep ones and add a course or two of masonry or pitch the roof above the window sills and lead box around the windows.

 

[Sonnypaul]

Have we not had this conversation already?

Ideally you would pitch the rafter to finish a couple of courses below the window sill in order to accommodate the flashing up-stand, the tile and batten.

If this happens to shallow out the roof too much, then you need to re-think the design. Either replace the windows with less deep ones and add a course or two of masonry or pitch the roof above the window sills and lead box around the windows.

Hi noseall.

The brickie finished today and I pitched up a 6x2 rafter with a 2 inch birdmouth and as luck would have it the top of the rafter was 150mm down from the sill, minus tile battern and upstand.

For some reason noseall I thought I wouldn't have to go right under the sill because the extension is only going out 2500mm rather then the norm 3000m

 

[noseall]

For some reason noseall I thought I wouldn't have to go right under the sill because the extension is only going out 2500mm rather then the norm 3000m

You let the maths and the pitch of the rafter dictate where the rafter finishes irrespective of the size of the extension or the position of the upstairs window sills!

I'm getting a bit bogged down with your interpretation of things, i.e. you seem to think that the rafter has a pre-set position - it does not.

Decide on a pitch. Cut a rafter and b/m to that pitch and try it in position. If it happens to land ten courses below the sills - hoorah, crack on.

If however it lands directly under the sill, then you need to re-thing the design.

150mm down from the sill is tight but do-able. You will end up with a small upstand of lead under the windows which will be protected by the sills in any case. Just make sure you chase the lead in PRIOR to fixing any tiles.

 

[Sonnypaul]

For some reason noseall I thought I wouldn't have to go right under the sill because the extension is only going out 2500mm rather then the norm 3000m

You let the maths and the pitch of the rafter dictate where the rafter finishes irrespective of the size of the extension or the position of the upstairs window sills!

I'm getting a bit bogged down with your interpretation of things, i.e. you seem to think that the rafter has a pre-set position - it does not.

Decide on a pitch. Cut a rafter and b/m to that pitch and try it in position. If it happens to land ten courses below the sills - hoorah, crack on.

If however it lands directly under the sill, then you need to re-thing the design.

150mm down from the sill is tight but do-able. You will end up with a small upstand of lead under the windows which will be protected by the sills in any case. Just make sure you chase the lead in PRIOR to fixing any tiles.

Hi noseall, thanks for replying.

When you say find a pitch I'm happy with, what do you mean?

If I was using 49s smooth for example, should I just pitch my roof at 17.5, the minimum pitch..
I would of thought higher the pitch the better.

 

[noseall]

Yes, the higher the better.
Aiming for two courses below the sills is fine as long as you deal with the lead chase before fixing any rafters.

 

[Sonnypaul]

Yes, the higher the better.
Aiming for two courses below the sills is fine as long as you deal with the lead chase before fixing any rafters.

Cheers noseall, the reason I always post the same question is because sometimes I see extensions that go out 3 meters and the roof is like 3 courses below to finished tile!

Think to myself how on earth did they get 17.5 degrees

 

[noseall]

Cheers noseall, the reason I always post the same question is because sometimes I see extensions that go out 3 meters and the roof is like 3 courses below to finished tile!

Think to myself how on earth did they get 17.5 degrees

Shallow upstairs windows.