Damp wall and floor lifting - vents causing this?

bluedrop

Hi All,

I have 2 separate issues

Issue1: My solid oak floor that was laid 2 months ago started to lift. The guy who laid the flooring came back and removed the beading to check. There was still space to move (even though very little in some cases). He then removed a few rows and said will come back later to check if it has settled down.

I have a through lounge. There is an external vent exactly below the garden door. If you draw a line from the vent to the other end of the lounge/diner, thats where the floor lifted. On the other side of this "line", there is another external vent.

Could the rains + vent have caused this?

Issue 2:
I live in a typical 1930s semi. My hallway is the detached side. I noticed a palm sized damp patch on the hall way wall just above the skirting. The other side of this wall has a vent !! I am not sure if the vent is exactly where this damp is. But its approximately in the same are.


Do I have some serious problems with the vents? I am worried about what the moisture will cause in the winters when just 3 days of rain can cause this!!

How do I resolve this???

osdset

By vents do you mean air bricks? If so they should all be situated below floor level as they exist to ventilate the space under the floor and should be kept clear of debris.

Is there evidence of any damp patches under the new floor?

You mention there is little expansion space for the floor to move in some areas, I would allow 10 to 15 mm expansion gap all around to be on the safe side, it's easy to underestimate just how much wood can expand and contract.

If the floor lifts again and there is no damp underneath it, my money would be on the expansion gap.

Issue 2

If your property was built in the early 30's it might not have cavity walls, you can check this by looking at the brickwork from the outside


If yours is solid you might be getting water ingress because of a faulty damp course. This can effect a cavity wall as well, I am not going to mention rising damp because this causes loads of arguments about whether it exists or not, suffice to say solid walls can, and do lead to damp problems.

If you have cavity walls and damp is appearing, and it cannot be attributed to a leaky pipe for instance I would suspect that something is bridging the cavity.

The air bricks should not be causing damp in the walls as they are below floor level and therefore below the damp course.

bluedrop

I have no clue about the bricks. The brickwork is not visible

The external vents look like this:

[IMG]http://forums.moneysavingexpert.com/C:\Documents and Settings\6528358\Desktop\vent.JPEG[/IMG]

Sorry, unable to attach a picture.

First google result in images tab for "external floor level vent"

osdset

bluedrop wrote: »

I have no clue about the bricks. The brickwork is not visible

The external vents look like this:

[IMG]http://forums.moneysavingexpert.com/C:\Documents and Settings\6528358\Desktop\vent.JPEG[/IMG]

No picture

Ok you will have to measure the thickness of the walls.To measure the thickness of your outside walls, open your front or back door (or a window in the front or back walls) and measure from the outside face of the wall, through the door/window opening to the inside face of the wall.

If the thickness is more than 300mm(11.5") you have cavity walls.

osdset

This one ?



That's an air brick, and it's blocked.

bluedrop

osdset wrote: »

This one ?



That's an air brick, and it's blocked.

Yes! The external vents look like this!!

Mine dont appear blocked though.

Can these cause dampness in the house?

osdset

bluedrop wrote: »

Yes! The external vents look like this!!

Mine dont appear blocked though.

Can these cause dampness in the house?

They can exacerbate an existing problem if in the wrong place (unlikely), or the level of the ground outside has been raised a significant amount, (paving for example) or blocked, if you have a leak or flood under a floor void, the air bricks allow air flow to ventilate the void and dry the moisture out, if the air bricks are blocked the void gets no airflow, the moisture takes forever to dry out and can aid mold and possibly dry rot.

As I said before the air bricks should be under damp course level if there is damp higher up the wall it's probably something else.

cyclonebri1

They are quite often above dpc, to vent bathrooms and kitchens, pantries etc, exactly the same as that but a little higher, no reason for them to be associated with damp to be honest. Even as late as the 60's they where installed like that.

They should be sleeved through the cavity and sloped to ensure no rainwater run in.

sk240

If the floor is lifting it is probably either the floor & or insulation is uneven, or there is anot enpugh gap around the edges for expansion

bluedrop

Update:
The fitter came in and checked. The expansion gap was still there. He however removed some planks at the end and asked us to put weights on the buckle. After a few days, it settled down. The fitter laid the planks and left.

Now the problem is, Whenever it rains, the floor buckles. Not as much as before, but its visible.

. Is this because those planks are no longer attached to the floor? Or do I have a bigger problem? Appreciate thoughts on this....

cyclonebri1

How where the oak floorings laid in the 1st place, ie, were they nailed, glued to each other and the floor, or just glued to each other.

The point is it either needs to be fully floating or fully fixed, the fact that you say he has removed a section of flooring makes me wonder.

If the floor isn't fixed, the weight of furniture can cause solid wood to lift during periods of high humidity as it can prevent expansion. It becomes easier for it to lift rather than to push out towards the walls.