Waterproofing a coal cellar

[kingandy2nd]

Hi all,

We have a coal cellar in our house which I’d really like to make waterproof and would like some suggestions on how to do this,

I’ve attached some pictures of the part of the cellar that’s outside our front door and from where the water seems to be coming in.

The old coal hatch is still present, but has been concreted in. However, from below the whole of the concrete slab that the hatch is in seems to be damp, the water is dripping from the piece of wood that has been presumably put in place to hold the concrete when the coal hatch was filled.

I’m apt at rendering, and have half a tub of tanking kit left over from a shower project. Would either of these be the routes to take or do you think the whole concrete slab is shot and will need to be replaced?

Any other suggestions of what to do would be welcome too!!

Thanks!

Untitled

• kingandy2nd
• 11 Oct 2008
• 1

Untitled

• kingandy2nd
• 11 Oct 2008
• 1

Untitled

• kingandy2nd
• 11 Oct 2008
• 1

 

[weseeyou]

well it depends on what you intend to use the coal cellar for . It will be under the ground and likely to have no damp proof course or damp proof membrane . You'll probably need to put in a DPM and dryline the walls if its damp.

 

[onlymem82000]

Hi ya

If you want some good options try this site

www.sika.co.uk

this company makes tanking chemicals and Concrete Repair and Protection products,

they also give downloads on products and how to use them

 

[mattylad]

Wont drylining the walls just allow dampness up behind the drylining?

It seems that the problem is the incoming water, which needs sorting out first
good and proper, because if its not done 100% forever then anything done inside canget ruined later on, so I would be removing as much of the slab up top & replacing it all rather than just filling in a little bit.

I have a similar problem with my coal cellar, but I dont think its the coal hole itself thats leaking.
Kingandy, something to consider before you completely fill the hole all in, is airflow & where to pump out any flooding.

You might like to think along the lines of putting a above ground vent pipe in and another that you can pump water out through while your filling in & sealing. (Obviously they need to stick up a few more inches than ground level & are not open to rain.).

 

[jeepman]

Hi if you want to know all about dampproofing a very good company to help you out are bluebay building products
they are based in cardiff/swindon/luton/newcastle they stock a very wide range of products and are very helpful and will deliver as well
the website address is www.bluebaybp.co.uk

 

[kingandy2nd]

I just wish to use the cellar for storage, but would like it to be dry storage.

Weeseeyou – can you provide a bit more of an explanation on how to use a DPM in your scenario? Bare in mind that the walls are brick, with a concrete roof (on the area that protrudes outside of the footprint of the house) and concrete floor. I just can’t see how a DMP could be fixed, nor how this would be effective unless it encapsulated the whole cellar?

Mattylad – thanks for your thoughts. We don’t live in an area prone to flooding, so don’t think that pumping out needs to be considered. The cellar also has the access to the crawl space under the house (which in turn has air bricks) so there is some ventilation.

Onlymem/Jeepman – thanks for the links. I’ve got some Mapei tanking stuff at home and thought it was good for my shower. I think the Idrosilex Pronto product may be just what I need.

I think I will first go down the route of trying to waterproof what is already there, before thinking about doing any major work such as replacing the slab.

Thanks for your time!!

 

[kevintaylore]

It looks like the cellar wall already has some kind of paint or coating on it. This will make it difficult to apply a tanking slurry (like the Mapei product you have) without doing a lot of surface preparation - e.g. bush hammering, grit blasting. The easiser method is to use what is called a cavity drainage membrane (e.g. Oldroyd, Newton) - these are fixed onto the wall without any preparation and allow any damp to drain away behind them. Really they should be used with a sump and pump, but if you are sure that your cellar is damp and will never flood you could get away without a sump and pump (at your own risk).

 

[kingandy2nd]

Yes there's a coat of matt masionary paint on the walls.

I think the main source of the damp is rainwater coming through/around the concrete slab on the top of the cellar rather than penetrating damp coming through the walls.

I'll see what I can do with the tanking stuff I've got to hand and feedback for the benefit of anyone else with a similar problem.

Thanks again!!