Damp Subfloor

[DrewMR]

Hi

Appreciate any advice on this one here:

Noticed damp patches forming above skirting board on plastered walls.

Have seen that water is coming in at cove joint where first course of bricks are bedded into concrete footing (First Pic).

http://tinyurl.com/ll5uldv

It's not a lot of water but sub floor ground surface is constantly damp; you will see that mould has formed on the brick work where condensation has occurred and not been vented away.

All this condensation i believe has transferred from the brick and moist air into end of some joists and rotted them.

This has not been helped by an air vent subsiding due to wooden lintel rotting.

Second Pic shows bigger picture.

http://tinyurl.com/mztjjr8



Any thoughts what I should do?

Thanks for any suggestions, much appreciated.

 

[jeds]

Water collecting in the floor void isn't ideal but it is also quite common and shouldn't really be a problem if the void is well ventilated. What is the state of the ventilation and external ground. How do external levels relate to internal?

 

[DrewMR]

Water collecting in the floor void isn't ideal but it is also quite common and shouldn't really be a problem if the void is well ventilated. What is the state of the ventilation and external ground. How do external levels relate to internal?

Thanks Jeds; ventilation has not been fantastic, the air vent on left second pic had collapsed but it is onto a bare ground floor so I really would like to stop any source of damp under the floor to start with.

Subfloor level is below ground level outside, a sloping drive in direction of house so water will want to penetrate as a matter of course.

Was thinking about grinding back the brick/footing joint and repointing to see if this fixed things.

Hope you can see the pics, brick work not fantastic at internal wall above subsided air vent, can i simply insert new piece of wood as lintel and re brick above?

Thanks

 

[jeds]

Don't underestimate the effect of ventilation. An apparently dry sub-floor with no ventilation will cause a problem whereas a very wet floor with good ventilation will not. Any reasonable step you can take to keep water out may be worth doing but it will be worthless without good ventilation.

Looking at your wall plate and joists; you could work along three or four bricks at a time laying a new plate with a dpc beneath and lapped up the back. If you are replacing joist ends encase them in poly sheet. Then make good bricks around. Otherwise bite the bullet and support the floor and do the lot in one go.