A DIY Question

[Kryten]

Over the weekend I noticed that where the book case in the living room has been up against the skirting board, the skirting board itself is now starting to show signs of damp. The book case is one of those ones which has a contoured lower section so that it will stand upright against both the wall and the skirting board itself.

Given that the house is new, and was only painted a month before I moved in, is it possible that the skirting board, whilst dry, has being giving off moisture which has been trapped by the book case and thus caused the paint to crack and mould to set in? Can furniture cause condensation in a single spot?

I should point out that there is no sign of a leak along the wall or on the first floor, and that I have run water / turned heating on and there is no sign of a leak.

 

[busby1971]

If you're in a new home there'll be loads of moisture in the house, your skirting would be dry but your walls will be damp, especially the external ones.

Bring the case off the wall and let some air get to it, screw or stick a couple of those little rubber door stops to the top of the bookcase for a month or so whilst the heating is on and the problem should clear up. Wipe the wall with some biocide to kill to mould.

I just painted my lounge and found damp behind a painting on the wall, shouldn't be any thing to worry about, my house is about 18 months old.

 

[needsabiggerfuse]

£ to pinch of the smelly stuff, the decorator painted over plaster that was barely dry, i.e. pink on the surface but still wet underneath, before he went on to the next job. That water has to go somewhere and has also been trapped by your bookcase.

Solution, lots of fresh air, open the windows (What in winter time!!!???), or get a dehumidifier (You'd be surprised). Don't pump up the heat, 'cos all you'll do is dry out the surface and then wonder why you've got cracks all over the place.

 

[Gord]

According to a mate of mine who is a plasterer, plaster never fully dries out as it absorbs moisture from the air, if it does completely dry due to excess heat, then as mentioned above it will begin to crack.A bleach solution will remove and kill off any mould just don't wet it down too much

 

[Ex-Bay]

I suggest a small de-humidifier standing near the affected part.
A small gap will help a great deal.
Or so I am reliably informed
DT_Xtremez_14:

 

[Kryten]

Thanks guys - I had a sneaking suspicion that it was probably moisture from the paint drying out and being trapped by the book case - but as someone with all the DIY skills of an amoeba I just needed to check to see that the paint giving off moisture was a feasible cause....DT_Xtremez_19:

 

[Gord]

Thanks guys - I had a sneaking suspicion that it was probably moisture from the paint drying out and being trapped by the book case - but as someone with all the DIY skills of an amoeba I just needed to check to see that the paint giving off moisture was a feasible cause....DT_Xtremez_19:

The moisture wouldn't be from the paint mate, it would more likely be from the paint not allowing the plaster to dry properly by trapping the moisture in until it could do so no longer as the mould would begin to break down the surface adhesion of the paint, as has already been mentioned here.

 

[Gonterseed]

Ok Kryten, and now for the doom laden post...

I must admit that a bit of mould on the skirting board does seem a bit strange. 99% of new builds (extensions and complete houses) have dry-lined walls.

Dry-lining is basically done by gluing dry plasterboard to the wall. The wet plaster is basically a couple of millimetres of skim on top of that and it dries out pretty quickly. There will also be a 5 to 10mm air gap behind the plaster-board and the solid wall so there is unlikely to be any damp problems caused through drying out, even if it is painted on as soon as the skim of plaster goes off.

If your walls are dry-lined, you can tell by tapping them - they sound hollow, then there is likely to be some damp coming in from somewhere or, if it's an outside wall, it might have a "cold spot" with a gap in insulation causing condensation. Or, it might be that the room isn't properly ventilated - air-brick or window vent. Worst case, in a dry-lined wall, is a tiny leak which will run down the behind the plaster-board and settle on the floor and then you end up with damp at the bottom but not at the top. Or it may a dozen other problems, or none at all.

Given that it's a new house, I'd give the builder a call and ask them to check, at least then you'll know for sure.

 

[Kryten]

Ok Kryten, and now for the doom laden post...

I must admit that a bit of mould on the skirting board does seem a bit strange. 99% of new builds (extensions and complete houses) have dry-lined walls.

Dry-lining is basically done by gluing dry plasterboard to the wall. The wet plaster is basically a couple of millimetres of skim on top of that and it dries out pretty quickly. There will also be a 5 to 10mm air gap behind the plaster-board and the solid wall so there is unlikely to be any damp problems caused through drying out, even if it is painted on as soon as the skim of plaster goes off.

If your walls are dry-lined, you can tell by tapping them - they sound hollow, then there is likely to be some damp coming in from somewhere or, if it's an outside wall, it might have a "cold spot" with a gap in insulation causing condensation. Or, it might be that the room isn't properly ventilated - air-brick or window vent. Worst case, in a dry-lined wall, is a tiny leak which will run down the behind the plaster-board and settle on the floor and then you end up with damp at the bottom but not at the top. Or it may a dozen other problems, or none at all.

Given that it's a new house, I'd give the builder a call and ask them to check, at least then you'll know for sure.

I have someone coming out next Wednesday, but just to clarify - the only mould is on the carpet fix rail around the wall in question and on the underside of the carpet. I have had the carpet and the underlay up in that area and they are dry, as is the floor itself. The skirting board itself is now dry and is mould free -the only visible sign is that the paint is cracked and feels rough to the touch.

The reason I wondered if it was condensation is that it has appeared in the exact spot where this bookcase used to be, and as I mentioned the bookcase is shaped so that it can go flush against the skirting board and the wall. I was wondering if during the drying out process any moisture would be trapped in the cavity formed by the front and sides of the shelf and with no ventilation it would just sit on the paint?

You mentioned that it could be a tiny leak which could run down the behind the plaster-board and settle on the floor - wouldn't that leave a tell tale mark on the wall itself?

Now in Worry Mode.

 

[babysitter]

Is it black mould? Most likely ventilition issue form having the bookcase too close to the wall and trapping condensation. Wipe off with bleach and move bookcase and inch or two back.

 

[Gonterseed]

I have someone coming out next Wednesday....

You mentioned that it could be a tiny leak which could run down the behind the plaster-board and settle on the floor - wouldn't that leave a tell tale mark on the wall itself?

Now in Worry Mode.

Tiny leaks don't always touch the plasterboard. The plasterboard is fixed to the hard wall with blobs of fixing compound and unless the path of the leak from the top (or part way down the wall) is interrupted by a blob then it won't show on the plaster-board until it hits the bottom.

Sorry, wasn't trying to worry you, it's just that it's unusual to get mould in a place that wouldn't normally suffer from condensation or drying out of plaster. Whatever the problem is/was you've now done the best course of action by getting someone to look at it.

 

[Kryten]

Tiny leaks don't always touch the plasterboard. The plasterboard is fixed to the hard wall with blobs of fixing compound and unless the path of the leak from the top (or part way down the wall) is interrupted by a blob then it won't show on the plaster-board until it hits the bottom.

Sorry, wasn't trying to worry you, it's just that it's unusual to get mould in a place that wouldn't normally suffer from condensation or drying out of plaster. Whatever the problem is/was you've now done the best course of action by getting someone to look at it.

Thanks mate - as I said it just seemed too much of a coincidence that this area of dried up damp is in an area of skirting board that was behind a book case and nowhere else...and that its not near any window or radiator....but I'll let the guy check it out and we'll see what happens.

 

[needsabiggerfuse]

Was in our local Al*i earlier today. They had a stack of mini dehumidifiers on sale for just over £22 a pop.

 

[Kryten]

Might nip into ours and get one!

Incidentally I spoke to one of the builders yesterday who in a stroke of genius actually lives round the corner in a flat on the estate - he has said he reckons it's condensation trapped by the book case, as he is aware that other people on the estate have had a similar problem. He's going to pop round tonight and have a look...