Capping a cavity wall

[martyc]

Hi,
I need to cap a cavity wall with something like these!

http://www.facingstone.com/picture/bluestone_wallcappingcill.jpg

Should i first "close the cavity" with block?

Or should i just get capping wide enough and put it straight on...also should i put some DPC across the whole thing first?

Cheers,
Marty.

 

[noseall]

are you talking about a parapet wall or simply closing a cavity off at the eaves?

 

[martyc]

Its just the front wall of my garage....it conceals the lean to behind it(lean to is a side abuttment to this wall...the one i need soakers for!) and its a cavity wall all the way up and i just need to cap it off
Marty

 

[noseall]

so this wall is a parapet then?

 

[martyc]

No!! i need aterminology lesson!

Its just a front wall of my garage...my parapet is my boundary/party wall...the front wall conceals the roof(its highest point is about 6 inches higher than my ridge )
Basically its a stand alone cavity wall that needs to be capped
Marty

 

[noseall]

oh.

put some paving slabs on it then.

 

[martyc]

Sounds like a plan...i assume they arent pourous
Marty

 

[sbdobson]

Marty c do you have any information on the parapet party wall?

I plan to have lean to monopitch roof for a kitchen extension. The roof will drain into a box gutter which is located on the party wall.

i cant find any information on it except for flat roofs, or kingspan steel frame buildings.

Mine is a simple brick, cavity , blockwork with timber rafters but no ceiling joists.

if you can help I would be so grateful

cheers

 

[martyc]

Yeah i built one of these in 2007!!
The key for me was the gutter...i bought mine from gutterline in the UK (im in ireland)...it worked out really well.
What info do you need?
I think you should have joists tho to prevent spread unless you have something else in there to restrain it.
Feel free to ask and ill try to answer.
Marty.

 

[sbdobson]

Cheers Martyc for the message.

I will check it out the company.

Where did you get your technical info from? I cant find any anywhere. I was looking for a simple detail of how the roof would join a parapet gutter. Ive never had to do such a detail not even for a flat roof and non of my friends in the industry are sure.

cheers

 

[JohnCo]

Your ceiling joists will have to sit on a plate inboard of the party wall supported on either a steel or timber lintol. The facia board needs to fit close to the gutter so that the tiles hang 50mm over. Before felting the roof it is good practice to seal something from the top of the rafters to the inside of the gutter, ( we use a pre-formed fibreglass flat roof trim) using sikaflex actually in the gutter. Hope this helps. Regards JohnC.

 

[sbdobson]

Thanks JohnCo

Im just bit confused by what you mean by the ceiling joists. Just I am hoping not to use them so that the ceiling is vaulted. Did you mean rafters instead?

Thanks for the tip of the fibreglass roof trim will look it up now.

cheer again

 

[JohnCo]

A typo! I forgot you were having the ceiling on the rafters! You don`t have to use fibreglass, plastic dpc will do the same job - it`s just not so durable. Regards JohnC.

 

[martyc]

The way i did mine, i originally had a single block party wall.
I built an inner leaf inside it.and i dropped my wall plate on the inner wall.
Joists and rafters ~(yove no joists but as long as you prevent spread you should be OK)

I put a facia board on the joist ends and i installed the gutter.
I had my gutter made so that it went under the capping on the external wall, down the parapet...across the bottom 4 inches(cavity essentially) up the fascia board and then under the roof cladding by about 10 inches...job done.
Look up that crowd gutterline and they will make you a gutter liner that will do the sam...the whole thing is sealed.(and it was cheap too!!)
MArty.