DPC above new cavity wall lintel

[snapfish]

We are looking at putting a new window into a cavity wall. Ive put in a couple of internal lintels before but never in a cavity wall. I am slightly worried about the DPC as most cavity wall lintels mentions DPC required. Searching the internet there isn’t much information on how to install a DPC on a retrofit lintel. We found a Catnic CG50/100 lintel 2100mm long and on there website it mentions it has a build in DPC.
Using this lintel, would this eliminate me having to put in a separate DPC?
Or is there anyone who could explain how to install a DPC above the lintel.

 

[^woody^]

The shape of the catnic boot lintel, means that it functions as a cavity tray. Don't forget the weep holes

 

[snapfish]

Thanks woody for your quick reply. So is what your saying all cavity wall lintel with a slope in the cavity don’t need a DPC sheet above the lintel and only need weep holes through the mortar.

When looking at other makes of lintels the diagrams show a DPC sheets included. Is this not necessary?

http://iglintels.com/lintels/standa...0mm-outer-leaf-lintels/standard-load-lintels/

 

[tony1851]

Except in areas of severe exposure, the coating on Catnic lintels (plus their shape) eliminates the need for a separate DPC.
Other lintes, such as galvanised steel types, do need a separate DPC over them. Retro-fitting one is a pain, so make life easy and fit a Catnic

 

[^woody^]

No I did not say that. I said that the lintel , in the shape of a boot which is made by the Catnic company does not need a cavity tray.

 

[snapfish]

Thanks for explaining that, I will put in a catnic one in, it looks a pain putting in a separate DPC. Would I still need to put in weep holes. Are they just plastic holes which go through the mortar.

Sorry woody I just googled boot lintels so I know what you mean now. I was looking at putting in the type which is in the link

 

[trowlerman]

yep agree with woody catnic all the way

 

[waltonconstruction]

As i am aware the point of a DPC above a lintel is to stop corrosion of the lintel by water in the cavity. It should also direct any water to the outer leaf to escape via weep holes.

From what i can remember many common 'Catnic' lintels have a 'built in DPC, which means its designed and protected in a way that a DPC is not required.

As long as the lintel (go for a catnic) has a 'built in DPC' and any water is directed to the outer leaf, you'll be fine. (don't forget weep holes)

Hope his helps

 

[waltonconstruction]

Just had a quick read up on this. I still think what i have said is correct although you may want t read page 76 of the following document. Seems to me that weather and exposure plays a part in deciding if you require a dpc.

Interesting....

http://www.catnic.com/libraries/document/Lintelproductselector.pdf

 

[noseall]

I found out only recently that by using Crown dri-therm cavity batts you are in effect creating a moisture barrier due to their water repelling construction.

A bit like having a sheet of polythene in the cavity.

Still need weep vents though.