Dwarf Wall / Floor Question

[ibruceuk]

Hi,

I'm building a shed type lean to thingy on the end of my kitchen. At the moment I have the roof up and am looking at the walls now. The current yard (concrete) has a slight slope to the house. To keep wood from contacting the ground I was going to support the struts to the roof on a brick and then put some temporary "shoring" <-spelling? up and pour concrete in (6:1 mix) that would encase the posts whilst them being off the ground and then panel the walls above this. The dwarf concrete wall would be approx 200mm thick and 300mm high to 400mm high at the lower end of the yard.

After this I will then be laying a screed inside the shed to about a depth of about 150mm (I was going to loose lay rubble for about half this depth to reduce the concrete required).

My questions are...

a) Does this plan sound ok?

b) Will I need to use some sort of visquine or similar under the walls and or under the screed?

Cheers for your help,

Ian.

 

[ibruceuk]

No comments????

 

[noseall]

 

[Bahco]

Same here.

 

[ibruceuk]

I'll try and make it slightly clearer than very gloopy mud!

Currently I have a concrete back yard up to the house.

I have constructed a lean to shelter at the rear of the kitchen (marked by the Red bit in the diagram)

Now rather than building the walls as wooden framework down to the floor I was thinking a small wall to prevent damp etc hitting the wood. I was going to make this wall from poured concrete as my brick laying skills are shocking. Also as the yard currently slopes towards the house I was going to pour concrete to level off the floor (there is a fall of about 150mm).

My query was whether or not I would need to use some sort of barrier between the yard concrete and my poured concrete to prevent damp rising. Also would I need something similar when I pour concrete for the floor. Or, is concrete impervious to water?

The wall will abut the house which is solid brick (no cavity) with an injected DPC which the floor wouldn't bridge, but the poured concrete wall would.

Does this make it a bit clearer???

Cheers,

Ian

 

[Bahco]

Don't think your concrete can go above the existing DPC or you will get damp problems.

You should also put a membrane below your new concrete as well as polystyrene sheets IMHO if you intend to spend time in there.

 

[marshman]

as the currant yard slopes towards your building where is the rain water going to go ?
you will need expansion foam strips between the concrete floor and wall ends against the house
+ a dpm between wall ends and house as you'll be bridging your house dpc.
I don't think you'll stop the damp rising in your wall unless you're buying a ready mix for it or you pour it in two layers
using rubber / bitumen emulsion painted between the layers.

 

[ibruceuk]

Cheers for your replies.

There will be a 'tunell' in drain pipe bedded into the floor to a surface drain to allow water to drain away. I'm not so bothered about damp rising in the dwarf wall so long as it doesn't affect the house/timber, so maybe after it's dryed I can paint a bitumen sealing layer on the top before the timber is put on it.

And I'll use foam expansion /DPC between the floor and house and between the wall and the house.

Cheers,

Ian