Is this damp in a new build house?

[blueharvester]

We moved into a new build house about a year ago. We noticed about 3 months ago that on the kitchen/sunroom wall the paint on the wall just above the skirting board started to become flaky. This immediately looked like it was water that had got down behind the cavity wall. We got the builder out who said it must've been water that had got in from the outside window sills which hadn't been sealed right. He then got them sealed.

However, we also noticed that the same thing was happening in one of our living rooms on an inner wall! Have a look at the following pictures here.

What could this be? Surely not damp in a brand new house?

 

[^woody^]

Dampness is going to cause some yellow/brown staining, do you have this?

It may be a reaction of the paint/caulk, or the plaster may be 'polished' so that the emulsion has not adhered. Also, it is common for areas like this to have been touched up for one reason or another before the sale, and the paint not taken properly. Then over time with little natural humidity flakes it off.

What floor and wall construction is it? Beam and block floor or timber floor (it will bounce) or solid concrete? Is the external wall plasterboarded (sounds hollow) or bonded and skimmed. Is the internal wall a stud timber wall (sounds hollow) or solid block

And is that a crack below/right of the window? Looks like a plasterboard joint crack

Do you mop those tiles?

 

[blueharvester]

There doesn't seem to be any yellow/brown staining, just the paint becoming powdery and flaking off.

All of the floors (in both rooms) are solid concrete and the walls are solid block. The skirting boards in the living room are just tacked on at the minute as we have yet to put floors down, so should I take the skirting off to see if there's any damp behind it?

Yes indeed that is a crack in the wall just to the right of the window, but that wall, as I said above, is solid block, not plasterboard. I assume that it's just settling cracks but I must note that we did get the builder to build the sunroom after the house had been built, so is this a cause for concern?

Yes, we mop the tiles, but we have no tiles in the living room so this shouldn't really be what's causing the problem, right?

 

[JerryM]

[/quote]paint becoming powdery and flaking off

this can be caused by dampness.

u need to hire a damp meter to get an idea whether it is or not.

if not then it's down to something not being quite right about the paint or how it was applied. i doubt this to be the case although it's possible eg it could be down to how the top edge of the skirting has been sealed to the wall ie the sealant ok for sealing the gap but not for overpainting. a good primer would fix for example.

if it is damp then there are a few possibilities. any residual build moisture should have gone in the 1st 6 months so their must be an ongoing cause. the trouble is in finding it.

1) condensation - how much water vapour u put into the house from living in it - boiling of pans etc compared to how much ventilation. do you feel this could be high. to check it for real you need a relative humidity meter and thermometer
2) defect in the build - where to start? penetrating through the wall, falling down the cavity, plaster bridging onto concrete floor. i think u might be best getting the NHBC to have a look or your own surveyor if u think this might be the case.

 

[^woody^]

Without seeing it, in the absence of any staining, and the specific location of the flaking paint, then it may be more likely to be an issue with the paint rather than damp.

The almost exact horizontal aspect of this flaking is not typical of damp coming up.

Another possibility is different brick/block in the wall causing a cooler surface and a cold spot for condensation

With regards to th crack, whilst the addition may move or settle differently, its unacceptable to have the internal finishes crack like this. The builder should have taken precautions. That crack is already quite pronounced, and is always going to be there no matter how much you try and fill it.

Can the builder confirm if the addition was actually tied to the existing house?

 

[blueharvester]

Now that I think about it, the moisture could be coming from drying clothes in these rooms. But we do keep the windows open on vent when drying the clothes, perhaps this is not enough ventilation. You think this may be the cause?

With regards to the crack, it has got slightly worse lately, but we cover it with some pictures. Is there much the builder can do to fix this crack?

 

[JerryM]

i'd say the clothes are causing it. do the drying in one room upstairs for a while (try to keep the window open a bit as you say u do already - a trickle is best if poss rather than gaping for a short time). scrape off the existing paint in a test area, leave it a week to dry, then repaint and wait to see what happens. with the clothes now upstairs drying then i hope the problem will go away.

if not then it's more serious. my gut feeling would be a cold bridge probably because the insulation batt in the cavity has not been installed to below the ground floor slab. the trouble is there can be many other causes hence the need for a surveyor or NHBC to investigate fully.

for me a crack's not a big issue as long as the foundation is sound ie it's historical and not growing worse. dig out the plaster either side with a saw blade and fill with decorators caulk. smooth the caulk with a flat blade scraper then use diluted washing up liquid 1:5 with water and blend in by hand.

if the crack reappears then u need to get the builder back.

 

[JohnD]

...Now that I think about it, the moisture could be coming from drying clothes in these rooms...

If you insist on draping wet washing about the house it will always be damp. You might as well throw buckets of water at the wall. Save up for a washing line.

//www.diynot.com/wiki/building:condensation_in_houses