Painting Tips and Tricks 8, Damp Problems
Damp Problems Down on the Farm
There's a number of decorating problems you can come up against when redecorating old property.
A friend of mine bought an old farm house and of course the owner gave it a quick lick of paint to get it sold; which is the normal thing to do when selling your house.
Over the following twelve months it became apparent he had a damp problem around his windows. Grey mold kept forming and no matter what he did to try and get rid of it, it just came back again.
Condensation Can Cause Damp Problems
Nine times out of ten damp problems are usually in ceiling areas up stairs, if it's a problem with the roof or with ceilings down stairs if you have plumbing problems. The fact that this was round his windows was good in a way, (you couldn't tell my friend that) with regard to identifying the sauce of the problem.
So what was cause. The fact that it was a farm house gives you a little clue in that the property stood alone in the middle of farm land, open to all the elements.
He told me, he thought it was just condensation, but the grey mold was all the way round the windows.
There's a Number of Things that can Cause Damp.
If your old farm house was built out of stone, as a lot where, it would have no cavity.
Problems usually start on the side of the house the wind and rain hits the most; over a number of years it can penetrate the wall through the lime and mortar mix (in this case) that was use to build it. In the summer the outside of the wall will dry out; and you may get a brief rest-bite on the inside; but come winter the damp will appear again.
Investigate all the options.
To prevent this happening remove the front course of stone around the window.
Once you have the front course of stone removed, it's a good idea at this point to check the window is in good condition then rebuild the wall using a sand and cement mix with may be a water proof solution in the mix.
If the house has a cavity, check that you don't have a problem near the roof edge. I've know on jobs gone by of small holes in the roof edge over the cavity; with no felt laid on the roof between the slate and the joist; which is the way all roofs were laid years ago. The rain was running down the roof and into the cavity and appearing as a damp pach half way down a wall in the down stairs living room.
Secondary Double Glazing can Cure your Damp Problem
In this case my friend wasn't to far away with his assumption. The cause was condensation running down the windows seeping into the lime and straw based plaster; starting under the window sill the mold then crept up the sides of the windows as more condensation seeped into the plaster at the bottom.
So how do you decorate the walls. He wanted to keep the original windows so he installed a secondary double glazing system. That in it's self stopped the condensation and really fixed the problem but it's not a good idea to paint over mold, especially with a water base paint.
First of all wash down the effected areas with neat bleach, this will kill the mold. Leave it for 24 hours, letting the central heating, or in his case the log fire, do it's job of drying out the walls.
Once dry you should be able to paint, but to give it a belt and braces job; a water based paint (emulsion or any water base paint) only feeds the mold and damp patches your trying to get rid of; your just adding water to water.
So paint the effected area with any oil based paint you might have lying round, undercoat, gloss, satin or egg shell as long as it's oil based; this will seal the area.
You can buy purpose made waterproof membrane solutions to seal inside walls; refer to the tin for drying times; then give it two coats of the wall paint you've chosen.