Hi

 

I'm currently building a small side extension. Block outer leaf as it will be rendered.

 

I'm going to cover the cavity during construction, but inevitably some rain water will get in. How does it escape? Are the blocks slightly porous or should i put in weep holes below DPC. Thanks

 

Sorry to add, it's engineering bricks below DPC

Edited December 15, 20241 yr by Professionally nosey
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Should not be a problem as ground is usually damp/wet at foundation level. Yes you could put In weep vents below DPC but frankly I think it’s a bit OTT but if it makes you feel better then crack on. 

Engineering bricks are definitely less porous than blocks or other bricks, but will allow moisture to pass over time.

 

As @joe90 said, it’s going to be pretty much permanently wet below ground anyway so I wouldn’t worry too much.

Great thanks very much both of you.