Heights and pitches?

[Sonnypaul]

Hi all.

When building a rear single storey extension am I right in thinking the wall plate height is 2400? 2100 from dpc to lintel height ( for doors ) then One course of blocks above to make 2400, does this sound like common practice?

And secondly when it comes to pitching the roof what angle do you go by?

If there's an upstairs window on the house wall is it a case of staying below the sill? ( this will give me my angle? )

Thank you..

 

[palaceray]

if you take the pitch below the window cill you may well find the pitch is too low for most slates and tiles.
you often need to take the pitch higher and have a small flat roof and two cheeks where the window is.

 

[Sonnypaul]

if you take the pitch below the window cill you may well find the pitch is too low for most slates and tiles.
you often need to take the pitch higher and have a small flat roof and two cheeks where the window is.

Hi palace, yeh I see what your saying but what about other extensions I've seen where the new block work is 2400mm to wall plate and still below the sill or even 3 or 4 bricks below sill and they still have 49ers?

Cheers fella

 

[catlad]

You have to take into consideration which type of roof covering you are going to use before deciding what pitch it will be.

 

[Sonnypaul]

You have to take into consideration which type of roof covering you are going to use before deciding what pitch it will be.

Hi catlad, the tiles are 49ers smooth, not sure what pitch they go from or to

 

[catlad]

min pitch is 17.5 degree's

 

[palaceray]

Everything we are saying is in general terms, we have no idea of the height of your windows or the depth of your extension which are both deciding factors.

 

[noseall]

You would typically assume 2.1m from dpc or floor level up to window and door head height.

Your wall plate height is then governed by the availability of space remaining once the lintel heights have been considered. This is usually dictated by any deeper lintels over wider patio doors etc.

The wall plate itself can be thinner than the standard 100mm x 75mm if you needed to pinch another inch.

If there are no governing parameters i.e neighbouring properties, other ceilings or deep lintels etc then the wall plate can be a fair bit lower than 2.4m.

As said actual roof pitch is dictated by roof covering type and first floor window sills.