Sealing stone underloor

[alexsee]

Hi, I have a house built in 1895, under the ground floor there is quite a void with clear air ventilation. There are various old services, cables, pipes etc and around them there seems to be large holes. My house is not damp at all, however, I can see the damp around the holes and as I am doing underfloor insulation at the minute I'm thinking it makes sense to clean these up and seal them. Should I just scrape off and then use a lime mortar or what do people reccomend about the process I should use? See images attached. Any advice is appreciated

 

[aockenden]

This is under your timber-suspended ground floor, correct? I would think ventilation under there from holes around utilities-inputs should be BENEFICIAL for keeping that underfloor area dry. Like you said, your house is not damp at all. Why bother potentially upsetting that good performance by starting to seal-up sources of ventilation under your floor?

 

[Flyfisher]

I agree and I'd go a bit further and suggest that all that ventilation is probably the reason WHY your house is not damp.

Tidy it up by all means, re-point any loose brickwork with lime mortar if necessary, but reduce the ventilation at your peril. If it ain't broke, don't fix it!

 

[alexsee]

Hi Aockenden and Flyfisher, thanks for getting back to me, yes this is under timber suspended ground floor. I was thinking as the walls under the holes are wet I would need to seal up to prevent to water getting in, but that does make sense to keep the ventilation. I guess i was concerned that the wet wall would degrade eventually, will leaving it not end up leading to structural issues?

 

[Flyfisher]

I'm guessing those walls are under the exterior ground so they are, in effect, forming a shallow cellar. Cellars are pretty much always damp, well mine is anyway, because of moisture in the ground moving through the wall. The important thing is to have good ventilation so that the moisture escapes before it can migrate into the house structure above. You stated that you have no damp problem in the house so that suggests the ventilation is working. Assuming it has been like this for many years or decades, it would suggest everything is in equilibrium and all is well.

As for a wet wall degrading eventually, I suppose that's possible but eventually can be a very long time. Think moated castles and houses. Think Venice. I wouldn't worry about it.