Hi, I'm hoping for some advice.

 

What problems might I encounter if I build a conservatory on top of an existing dwarf wall that is soaking wet and full of rainwater inside it's cavity?

 

Should I wait until spring when it's completely dry, or can I build upon it now? The dwarf wall consists of red brick on the outer, insulation in the centre (but it has a 2cm gap open to the weather all the way round) and thermal blocks on the inside.

 

Will I get damp problems or some other problem I have not thought about if I put the conservatory on top of it now, rather than wait for warmer dry weather?

 

Thanks.

Pictures to show context?

 

Is it only wet because it has been exposed and the rain has filled it up, or is it wet because it has no DPC and is wicking water from the ground?

Drill a few holes just above the DPM on the outside and let it drain using some of these if you are really worried. Get a DPM over the cavity to stop any more rain ingress

 

https://www.ebay.co.uk/itm/Cavity-Wall-Round-Drill-Weep-Vents-Refurbishment-Retrofit-Various-Colours-/184213149281?_trksid=p2349624.m46890.l49292

1 hour ago, ProDave said:

Pictures to show context?

 

Is it only wet because it has been exposed and the rain has filled it up, or is it wet because it has no DPC and is wicking water from the ground?

Yes, it was built in August and has been left uncovered and exposed to weather since then.

Just now, ChesterIOW said:

Yes, it was built in August and has been left uncovered and exposed to weather since then.

The DPC is intact .

I've put some cheap carrier type bag plastic over it to try and stop even more ingress. 

Is it rigid insulation or fluffy?

 

If rigid you could just go ahead.  If it is fluffy and looks ruinously wet, I would remove it and replace if wall ties allow.  You could use polystyrene beads, but choose a very calm day.