Damp proof course and raised external floor

[rborob]

I can't imagine that direct rain alone would fill that volume of trench in that location. Are you sure that the surface drain was not overloaded?

I am yes, the drain wasn't even struggling with the water, hence why I was confused. (the volume of rain did cause the collapse of a 12 foot sandstone wall close by). The rain was very heavy and lasted about 20 minutes.

 

[wessex101]

You would not want water in a cavity to raise humidity levels in any case.

Air bricks in that location would typically be for the under floor venting or radon

Agree on the first point, it is not ideal but neither is it a major drama. If they are just cavity vents you could brick them up, it was something that seemed popular in the 50's but doesn't really serve any useful purpose.

They look too high for sub-floor vents but as OP is ignoring my question I guess we will never know.

 

[rborob]

Agree on the first point, it is not ideal but neither is it a major drama. If they are just cavity vents you could brick them up, it was something that seemed popular in the 50's but doesn't really serve any useful purpose.

They look too high for sub-floor vents but as OP is ignoring my question I guess we will never know.

Hi wessex..i wasn't ignoring your question, but it seemed to be escalating between you and woody so I was steering clear. I don't know the answer to your question though. How would I be able to tell if they're cavity vents or the underfloor ones?

 

[stuart45]

How would I be able to tell if they're cavity vents or the underfloor ones?

If your floors are timber you need underfloor ventilation. If you have concrete floors you don't. Cavity vents usually had one at the top of the wall and one lower down just above DPC.

 

[rborob]

Definitely wooden boards underneath the first floor carpets

 

[wessex101]

Hi wessex..i wasn't ignoring your question, but it seemed to be escalating between you and woody so I was steering clear. I don't know the answer to your question though. How would I be able to tell if they're cavity vents or the underfloor ones?

Woody is my hero, I wouldn't dream of escalating anything.

Is your ground floor solid or suspended timber.....jump up and down does it sound solid or hollow?

As for the airbricks poke something in one of the holes and see how far it goes in, 6 inches and it only goes in to the cavity, if it keeps going then it passes right through the wall. Obviously any water in the external trench will do the same thing. Out of curiosity roughly how old is the house?

 

[^woody^]

but it seemed to be escalating between you and woody so I was steering clear.

I only escalate when shopping in Debenhams

 

[rborob]

Woody is my hero, I wouldn't dream of escalating anything.

Is your ground floor solid or suspended timber.....jump up and down does it sound solid or hollow?

As for the airbricks poke something in one of the holes and see how far it goes in, 6 inches and it only goes in to the cavity, if it keeps going then it passes right through the wall. Obviously any water in the external trench will do the same thing. Out of curiosity roughly how old is the house?

House is from the 60's, so around 60 years old. Not sure on ground floor..i jumped up and down...and it sounded solid...i could pull up the carpet and check under a wooden board maybe? Whole ground floor is going to be refloored in the next few months anyway. Will try your pointy stick method tomorrow though