DIYnot
Local | Network
   DIYnot > Forums
Local | Network
DIYnot Network Local DIYnot Network Local  
  Forum IndexForum Index     RulesRules    HelpHelp     Join FREERegister Free     About CookiesCookies     SearchSearch     LoginLogin 

Footings in chalk


 
Post new topic   Reply to topic    DIYnot.com Forum Index > Building
Search this topic :: View previous topic :: View next topic  
Author Message
baldy01

from United Kingdom

Joined: 21 Sep 2006
Posts: 151
Location: Cambridgeshire,
United Kingdom

PostPosted: Thu Sep 21, 2006 10:06 am Reply with quote

Hi all,

I'm new here so hello to everyone, hopefully this is a simple question to answer.

I'm putting in footings for a conservatory, the soil under my house is chalk and its only about 6 inches down. If I have solid chalk to lay my footings in do I really need to go to the regulation 600mm deep? I was intending to use a 450x250cm foundation, that extra 350mm is an extra 5 layers of subsoil brickwork for what actual gain? My plan was to dig down far enough to bury my footings and maybe 1 brick subsoil giving about 350mm from soil level to the base of the footing. As long as its all dug down to solid chalk shouldn't this be ok? One wall will be a single story high end wall, probably a cavity wall.

Cheers

Pete
Back to top
 Alert Moderators

If you do not want to see this advert, click here to login or if you are new click here to join free.
Static

from United Kingdom

Joined: 20 Dec 2005
Posts: 2026
Location: Sussex,
United Kingdom
Thanked: 167 times

PostPosted: Thu Sep 21, 2006 10:08 am Reply with quote

There are no regs for conservatories, so simply you can do what you like as its a temp structure.
But if you want it to last more than 5yrs then i would at least attempt to go below the frost zone.
Back to top
 Alert Moderators
baldy01

from United Kingdom

Joined: 21 Sep 2006
Posts: 151
Location: Cambridgeshire,
United Kingdom

PostPosted: Thu Sep 21, 2006 10:44 am Reply with quote

So the depth is to keep the concrete footings away from the frost? That does make sense, thanks.

I've read that a cheaper alternative to the extra subsoil brickwork is to fill the trench with more concrete. Can you tell me if this should be done as a separate operation to the basic foundation layer, i.e should you let the 250mm footing set before filling with more concrete, as you would let it set before bricklaying?

Thanks again for the help here, I'm in research mode as I like to ask the stupid questions BEFORE I get myself a mess!

Pete
Back to top
 Alert Moderators
gardeners26

from United Kingdom

Joined: 29 Sep 2005
Posts: 28
Location: Surrey,
United Kingdom

PostPosted: Thu Sep 21, 2006 8:24 pm Reply with quote

On Epsom Downs I also have solid chalk under only a few inches of soil. After ten years of building numerous structures with 'only' ten inch concrete foundations directly onto the chalk non have yet showed any signs of movement,cracks or failure.
Back to top
 Alert Moderators
Static

from United Kingdom

Joined: 20 Dec 2005
Posts: 2026
Location: Sussex,
United Kingdom
Thanked: 167 times

PostPosted: Fri Sep 22, 2006 8:10 am Reply with quote

Trench fill is done normally in one pour to the level you require. Remember to sort out levels of any drainage you have first
Back to top
 Alert Moderators
baldy01

from United Kingdom

Joined: 21 Sep 2006
Posts: 151
Location: Cambridgeshire,
United Kingdom

PostPosted: Fri Sep 22, 2006 9:12 am Reply with quote

Nice one, thanks guys.
Back to top
 Alert Moderators
Search this topic :: View previous topic :: View next topic  
Post new topic   Reply to topic    DIYnot.com Forum Index > Building All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
Similar Topics   Replies   Views   Posted 
fixing wall plate to clunch(chalk) wall 4 40 Tue Mar 11, 2014 6:32 pm
Concrete mix for footings for 1.2m high retaining wall 10 6920 Sun Sep 25, 2011 2:56 pm
The saga continues - FOOTINGS & BI 5 220 Thu Sep 29, 2011 1:27 pm
Quick question about Shuttering Ply/Footings 6 80 Sun Sep 25, 2011 2:56 pm
Extending existing conservatory base/footings 2 140 Sun Jul 10, 2011 11:17 am


 
DIYnot
Find an Expert | Find a Supplier | Search DIYnot.com
Network | Advertising | Newsletter
DIY | DIY How To | @home | DIY Wiki | DIY Forum
By using this site you agree to our Terms of Service / Disclaimer.
Please read our Privacy Policy. Copyright © 2000-2014 DIYnot Limited.