Wall height for OBS Board

[OrangeJuice09]

Hi,

A question whether the OBS board should sit on any of the leaf’s of wall.

I’m constructing a vented flat roof, the closest joist will be a few inches from the inner wall. Should the OBS sit on the brickwork to provide additional support?
See diagram and note I’ve left the inner wall lower, as not sure what the finished wall height should be and if a wall plate is needed (having said that, if a wall plate is fitted, it would be below the joists -leaving a void between the OBS and top of wall plate) ?

 

[kingandy2nd]

Hi,

You’d need a gable ladder in the end, resting on the inner wall. You’d want some kind of overhang on the outer wall fix your fascia and soffit to.

 

[OrangeJuice09]

The wall I'm referring to is on the side. The flat roof is sloping to the front.

 

[jks7492]

The wall I'm referring to is on the side. The flat roof is sloping to the front.

How are you going to finish your roof if you're not planning to have a fascia at the side?

Its OSB not OBS btw...

 

[OrangeJuice09]

Fascia will be added on the side but as its built up the neighbouring boundary, it cant have too much of an overhang.

 

[OrangeJuice09]

Hi,

You’d need a gable ladder in the end, resting on the inner wall. You’d want some kind of overhang on the outer wall fix your fascia and soffit to.

Do you mean something like this ? (found image of a pitched roof) - Is it required for a flat roof also?

 

[kingandy2nd]

Yes, that’s what you need to make.

You need to have the end piece of wood to nail your fascia too, even if it’s flush with the outer skin so the fascia sticks out by a couple of cm.

You can’t nail fascia to bricks/blocks as per your first picture.

Here’s a couple of shots of mine

 

[OrangeJuice09]

I like those pics - Great job

I noticed in your picture, that you used the same timber as the joists for the end panel. Is it required to build up the walls between the rungs to the same height of the OSB board ? (Just thinking from an insulation point of view)

 

[kingandy2nd]

I like those pics - Great job

I noticed in your picture, that you used the same timber as the joists for the end panel. Is it required to build up the walls between the rungs to the same height of the OSB board ? (Just thinking from an insulation point of view)

No problem. I would use the same wood height as otherwise where you meet at the corner you’ll have different heights where your fascias/soffits meet.

The correct way would be to build and install the gable, then build up the inner skin to nearly the OSB height, then install the insulation (continue the wall insulation up to that same height), then finally put the OSB on.