Rainwater in cavity

[jimmy342]

Hi,
I’ve just had a dwarf wall for a conservatory built and have noticed that there is rainwater in the cavity about 50mm deep after heavy rain earlier this week. The rainwater appears to be seeping in from the outside as when I empty the cavity wall it fills up slowly and I notice the water level around outside wall goes down. The water is still well below DPC level and I think it is coming in where the wall meets the foundation maybe through the pointing done at the foundation when the first brick course was laid.

Is this normal? Is it expected if there is water sitting outside the wall due to heavy rain that some is expected to seep in and eventually will subside as the outside dries? The soil is clay hence the water logging issue on the outside.

Thanks

 

[^woody^]

It should be filled with concrete to 150mm below ground level, and weep holes

 

[jimmy342]

Thanks at what level should the weep holes be put?

 

[^woody^]

Level with the concrete in the cavity, and the concrete angled towards the external leaf

 

[jimmy342]

If it’s level with the concrete in cavity which is 150mm below ground level will the holes also not be below ground level?

Also the water is pooling inside where the concrete slab floor will go. I assume that will not be an issue once the slab is down and roof on right? As water will not come under the foundation and penetratee up to floor right?

 

[noseall]

Level with the concrete in the cavity, and the concrete angled towards the external leaf

Lol.

Jimmy has had a conny built not an extension Woods. This means that they dug just below the turf and put in a concrete 'foundation' for the outer leaf only. Built the external masonry up to slab level then cast the slab using the outside masonry as a shutter. They then will have built the inner leaf up off the slab.

 

[noseall]

Is this normal?

For UPVC companies yes (see above).

 

[jimmy342]

Hi noseall they haven’t put the slab in yet. Just built the outer and inner leaf and dug out the centre ready for the hard core, insulation and slab. I was just asking that since the cavity is filling with water from outside rainwater probably coming in through the base of the foundation meeting the outer leaf. Woody said that need to fill with concrete up to 150mm below ground level and then put weep holes level with concrete. Then does this mean the weep holes will be below ground level and won’t that mean water will come into the cavity through the weep holes. Thanks

 

[noseall]

Hi noseall they haven’t put the slab in yet

Oh.