Water under my bungalow

Bendy_House

youth_leader said:

Sorry, yes I am semi detached, bad photo, it says party wall on the left.  

The damp/timber surveyor said he hoped that the builder had vented the concrete but couldn't tell until the floors were removed. 

Being semi, I would expect your main underfloor ventilation to run from the front to the back, so if that concrete floor hasn't had vent ducting added, you can assume that's the most likely cause.

As GDB asks, have you tried poking a stick through the back vents? What about a smouldering taper - do the rear vents draw or blow smoke if held to it?

stuart45

Air bricks are only really effective when placed on opposite flanks to give a good cross flow.

GDB2222

stuart45 said:

Air bricks are only really effective when placed on opposite flanks to give a good cross flow.

I haven't checked, but I assume that you can add fans to force a decent air flow?

Edit: I have checked, and the answer is yes. 

stuart45

That's one answer to the problem. The Yanks believe venting to be a bit old hat, and think sealed crawl spaces with conditioning units the way to go.

youth_leader

Thank you GDB222 I will have a look at the airbricks with a stick and the torch tomorrow. I don't understand how they work as they all seem higher than the floor?

I am on a water meter and don't think I have a leak but will try that too tomorrow.

It was also suggested the airbricks were compromised when the cavity wall insulation was put in.  

stuart45

Cavity wall insulation shouldn't affect the air bricks, as there should be liners going from the external bricks to the inner wall.

youth_leader

Thank you stuart45.  I will have a good look tomorrow.  

youth_leader

Just been out to check the airbricks with a torch and a stick.  The extension air bricks are all plastic and slatted like venetian blinds, and very low to the ground.  I couldn't see very well lying on the floor.  The first two I looked at have solid concrete just behind the slats.  

I went round to the side of the extension and poked two of them there - soft bouncy material.  

Looks like I need someone to check them all.  

ccluedo

youth_leader said:

Just been out to check the airbricks with a torch and a stick.  The extension air bricks are all plastic and slatted like venetian blinds, and very low to the ground.  I couldn't see very well lying on the floor.  The first two I looked at have solid concrete just behind the slats.  

I went round to the side of the extension and poked two of them there - soft bouncy material.  

Looks like I need someone to check them all.  

That may well be the problem, shouldn't be anything obstructing the free flow of air - fingers crossed!

youth_leader

I am amazed it could be as simple as that ccluedo, I wonder why the surveyor didn't suggest it before.  I must say they are so very low it was very difficult to see, I had to lie completely flat on my stomach.