Closing a cavity wall

[cyclonebri1]

Hi,
I'm building a quite large conservatory, 6m x 4m.

Now it's free standing, ie, not attached to the house.

It's dwarf wall construction on 3 sides.

The rear/back wall is effectively all brick to above eaves height.

Their is a return at each back corner of 900mm at each side up to above eaves.

This is to give support strength to the construction.

All walls are 50mm cavity construction.

Ok the question:

At the moment I am at about dwarf wall height all the way round.
How do I cap of the high back wall at say 3 bricks above eaves level and not bridge the cavity????

I should say that this is a double hipped design so the eaves height is level all the way round, hope that's clear.

My thought is to go the old way and insert a layer of slate at eaves level and cap with a paver or stone coping, but I am open to any other normally used methods/suggestions?

Cheers

 

[cyclonebri1]

Anyone any better idea

 

[cyclonebri1]

Ok, would the none "asbestos" cement asbestos board used for under cloaking tiles be an option.
I just don't want to risk a leak in the coping bleeding down the cavity but don't want to tray the last couple of courses of bricks with conventionasl dpc plastic because of wind exposure.


And have I offended someone

 

[r896neo]

I imagine you have no replies because it's hard to envisage what your doing?

Any chance of a sketch/photo? Is it a parapet rear wall extending above the eaves height with a box/ secret gutter? But that sound crazy and i can't think why you would do that?

 

[cyclonebri1]

Hi, sorry hadn't realised it wasn't clear. I'm not to clued on how to put up a picture so let me try to explain.

Ok, imagine this is a completely detached conservatory/greenhouse or orangery to give it it's correct term. It would have dwarf walls on all 4 sides to 600mm and plastic/glass to the eaves with a normal pitched polycarbonate roof.

But no conventional roof system is guaranteed to work that way at my sizes, they are all expected to have a soild wall to build up to that gives wind resistance etc.

So both the companies I've spoken to have insisted that the only way they will supply and guarantee the product is the create a solid rear wall (which will have 2 windows installed in it), This wall itself needs support by continuing the brickwork 900mm along the side walls so the rear wall in plan looks like this I_____I

The design of the conservatory is dual hipped, the type you'd use to fit to a bungalow with reduced eaves height, ie all 4 sides slop down from the central roof ridge, so yes will have a gutter up to the rear wall which I intend to be 2 or 3 bricks above gutter height then capped with "slabs"

I simply need the best method to ensure no cavity penetration from above whilst ensuring the damp course, with only a few courses of bricks above, does not allow the the structure to move.

Hope that's a little clearer

 

[r896neo]

You just need to cap it with a pressed concrete capping stone of some kind with a DPC under it. I think you know that and your question is just a double check to make sure your right?

If so then yes that is the right way to do it and no need to worry about the masonary above the dpc moving as long as it's bedded properly.

Also it might be a good idea to re-post under the heading

'parapet wall design/ detail'

as parapets can be troublesome damp wise and you want to get it right, especially the box gutter. It may be better to dress the whole lot in lead but i'm no expert on this so repost in building or roofing to double check the best way.

 

[cyclonebri1]

You just need to cap it with a pressed concrete capping stone of some kind with a DPC under it. I think you know that and your question is just a double check to make sure your right?

If so then yes that is the right way to do it and no need to worry about the masonary above the dpc moving as long as it's bedded properly.

Also it might be a good idea to re-post under the heading

'parapet wall design/ detail'

as parapets can be troublesome damp wise and you want to get it right, especially the box gutter. It may be better to dress the whole lot in lead but i'm no expert on this so repost in building or roofing to double check the best way.

Thanks for the reply, yes you did understand me correctly, I was just wanting something that would "adhere" like mortar and slate rather than the standard checkered plastic dpc.

However the problem has resolved by talking to another conservatory supplier. They say that their system is suitable to bolt down on top of the outer skin rather than butt up to the inner skin.
ie the roof would carry over the wall and the box gutter sit on the outer facing, a much better sounding idea altogether,

Cheers for the reply,

 

[r896neo]

Yes that sound much better, as i mentioned parapet walls are more of a last resort as they can be problomatic.