Cavity walls required or not?


Postby bornlivelife » Fri Nov 09, 2007 12:58 pm

If I build an extension onto a house, is the cavity wall and damp proof still required in the wall which was external but is now internal?

I want to put some concrete inside the cavity to seal it from rats
bornlivelife
Rank: Apprentice
Progress to next rank:
52.6%
Posts: 15
Joined: Fri Nov 09, 2007 11:06 am

Sponsor

Simply Build It

Postby philjjj » Sat Nov 10, 2007 8:47 am

THE POST BELOW IS NOT GOOD ADVICE. PLEASE DOUBLE CHECK EVERY POST BEFORE YOU SPEND MONEY. THIS COULD POTENTIALLY DAMAGE YOUR PROPRTY.

if it is now internal yes you can fill it or you could even knock it down if you put a lintel in!, the cavity is only for external walls to keep out damp and cold your new wall of your extension will take over that job!
philjjj
Rank: Labourer
Progress to next rank:
50%
Posts: 3
Joined: Sat Nov 10, 2007 8:29 am

Postby thedoctor » Sun Nov 11, 2007 7:17 pm

Please ingnore the reply above as the old external wall still sits on foundations underground and it is still possible, extension or not, that this wall could transfer damp up the wall to the inside of the property. In fact this can ONLY happen if you fill the cavity without inserting a damp proof course within the cavity, at the same height and overlapping the existing dpcs in the skins either side of the cavity.
thedoctor
Posts: 2451
Joined: Sat Apr 08, 2006 12:15 pm

Postby thedoctor » Sun Nov 11, 2007 7:52 pm

Please also note that once you turn an external wall into an internal wall you must provive a cavity tray in the cavity above the height of the extension if it is single story. This stops and moisture in the cavity dropping down into the cavity and potentially soaking the skins on the new internal wall. Once damp is in an internal wall it is extremely expensive operation to stop it.
thedoctor
Posts: 2451
Joined: Sat Apr 08, 2006 12:15 pm

Postby bornlivelife » Sun Nov 11, 2007 9:37 pm

thanks for your reply - i will recommend the forum now and apologise if i was a bit disappointed earlier
bornlivelife
Rank: Apprentice
Progress to next rank:
52.6%
Posts: 15
Joined: Fri Nov 09, 2007 11:06 am

Postby TheDoctor5 » Thu Jan 22, 2009 10:28 am

Last year 64% of the questions asked in our forum were answered within our DIY project pages at www.diydoctor.org.uk/projects.htm The project pages are now separated alphabetically and your answers are accompanied by diagrams and the ability to see, and buy, the tools and/or required to complete your project. Use our search box to look for your answer and save a great deal of time and money!
TheDoctor5
Posts: 1382
Joined: Tue Jan 20, 2009 9:17 am

Display posts from previous
Sort by
Order by



  • DIY How to Project Guides

  • DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!



 


  • Related Topics