Is it rising damp or just the house drying out?

Question

We are currently renovating a house. All of the old plaster was taken off and all walls have been re-plastered with board and dab mainly but some browning. Also all of the ceilings have been redone. In 2 of the downstairs room it looks like damp appearing where the dabs are. Would this be damp or would it just be because of the amount of plastering the house is drying out, also there is no heating in the property at the minute.

Answer 1

Did you have a new damp course fitted?  Or did you just take off the old plaster and go over it with plasterboard?  If you did not have a damp course put in, it could be that the house is damp and that the parts that are showing through are where it is penetrating.  Was the plaster damp before you removed it from the walls prior to putting on the plasterboard?

I would give it a week and then have a look again.  If it is still damp, chances are you will need to get a complete course done as dry lining which is what you have done by putting plasterboard on, will not hold back the damp.

Good luck.

:)

Sadly you were misinformed!  If the house has damp, it needs a damp proof course.  Plasterboard over it will not stop damp, it will come right back through.  I have been a project manager for 15 years and I promise you, if you have damp, you need to go back to whoever informed you incorrectly and also employ a damp proofing company - who will give you a 25year certificate on completion incase it comes back.

Also, unless you put up a wooden frame to put the plasterboard on the damp will just penetrate through again.  Putting up a frame first is known as dry lining, that allows air to circulate, but does not stop the damp, it just does not show up on the plasterboard walls.  If you dab the plasterboard and put directly on the damp walls, this will not allow air to circulate and will not stop your damp problem.  The only solution is to have a full damp proof course.

Good luck.

:)

Answer 2

The heating situation could be causing the problem as its job is to put hot dry air in the house, thats why it requires a humidifier, but if you are finding your house to humide at the moment, buy a de-humidifier to get rid of the humidity, also it helps on those hot humide summer days. But the moisture is probably from the lack of dry heat and may be from the plaster.

Answer 3

You should have drilled out the walls and injected them with damp-proofing cream or pressure-injected liquid damp proofing, then rendered the internal sides of the walls with sand+cement+damp inhibiting additive and then dot and dabbed.

Only by doing this can you be sure to prevent rising damp and penetrating damp.

Your best course of action is to remove your plasterboard and do the job properly. The plasterboard adhesive will act as a bridge between your damp walls and the plasterboard.