Solutions For Footings and Damp Proofing

[Skavenger]

Hi;

I have built a block based and timber framed workshop in my garden. You can see in my project build here that for one of the walls I used the existing garden wall however I had to dig below the existing footing.
I re-enforced the wall footings by underpinning them and have completed the build (apart from GRP roof and cladding).

I now need some advice on finishing off the footing (waterproofing and rendering).

The DPM from the floor extends and can cover the footing and where is has been temporarily covering the footing it has shown signs of condensation from moisture probably as in some places there is exposed earth.

I started to infill the gaps in the footing with concrete but decided to NOT put the DPM under the concrete thinking I would put it under the render. I then thought that the render would have nothing to adhere to, but then again neither would the concrete.

What would be the best solution to finish off the footing and ensure it is waterproof?

Side view looking towards the wall showing the DPM folded back and the original footing underpinned with blocks on concrete. My intention is to render on the top and sides of the original footing so that it becomes a step (not for walking on) against the back wall.

Pic showing where I have started to insert more concrete in advance of rendering:

Pic looking down onto the footing showing the DPM folded back:

 

[Ady J]

I posting here not because I'm a pro in these things, but its an interesting question your asking

my project has internal floor level under outside earth level (using steel reinforced retaining wall blocks around poursed with waterproof concrete to protect from outer earth level )

as I think it will be in your case I'm running DPM up the inside lower walls (even though I'm using concrete with additives in etc for the lower sides), was going to plaster board internally not render , the lower part of the plaster board will have adhesive on but I know not stick but should be strong as the large plasterboards will be stuck in all other upper areas + skirt board will have seal adhesive underside

interior damp protection No.1 imo

interested in reading other comments/thoughts though

PS
your outer ground level is above inner floor level here?
maybe you could rise the inner floor level more (after putting in the DPM) so its above damp level

 

[Skavenger]

I posting here not because I'm a pro in these things, but its an interesting question your asking

my project has internal floor level under outside earth level (using steel reinforced retaining wall blocks around poursed with waterproof concrete to protect from outer earth level )

as I think it will be in your case I'm running DPM up the inside lower walls (even though I'm using concrete with additives in etc for the lower sides), was going to plaster board internally not render , the lower part of the plaster board will have adhesive on but I know not stick but should be strong as the large plasterboards will be stuck in all other upper areas + skirt board will have seal adhesive underside

interior damp protection No.1 imo

interested in reading other comments/thoughts though

PS
your outer ground level is above inner floor level here?
maybe you could rise the inner floor level more (after putting in the DPM) so its above damp level

It may be a little confusing but on the wall concerned the outer ground level is probably a little higher than the inner floor level but I do not have the option of raising the floor level.

I think I will continue to fill the void areas between the underpinning of the footings with concrete and then render over the top onto the concrete and cut the DPM at floor level. But first need to find out how to waterproof render?

 

[Ady J]

Can you put a vertical DPM on outside if you already have a trench going down the side of foundation rising just above ground level

+inject bricks with damp proof
drill hole(s) in each brick & inject into each brick just below & few above outer ground level

The outer vertical DPM will help reduce or stop water coming in from side the Impregnated bricks will stop rising damp

May take a few methods to make inside nice & dry