Dabs showing through mist coated walls.

JustAnotherSaver

Years ago we had our damp walls boarded & the dabs showed through. We later found out why - mould started growing on the dabs pretty rapidly.

This was removed. We had proper soveriegn approved damp proofers come in to do the K11 system fully & properly. They boarded the party wall out.

The dabs took a while to go & we thought oh no here we go again. They said it'll take time but they'll go. Sure enough the dabs actually disappeared. WooHoo & all that.

That was December 2015.

I mist coated it today using Dulux Trade SuperMatt. Ok the mix was probably too watery .... 50/50.

In the past few days i'd dampened down the walls to remove dust & such and no dabs showed through.

Put the mist coat on today & dabs are showing ... even way up at the top of the walls.

The chimney breast is only about 2 months since it was done (boarded).

The photos are more noticeable in person or on my phone. They don't seem the same when i put them on my PC but you can still get an idea...





Is this normal with such a watery mix?

Makes me wonder...

* just keep layering up with thicker mixes (like 90:10)
* do i need to put a stain blocker on? If so what?
* i read to put an oil based undercoat - but then how does water based emulsion get on going on top of that (water on oil?)? Straight oil based or thinned down - if so to what?
* in addition to the above - Sovereign chemicals say any paintwork can't be a 'vapour barrier' with the K11 system. Is all oil based undercoat a 'vapour barrier'?


Basically just what to do to deal with this. The damp itself can't surely be getting through as i watched them go through each step as they layered it all up.

DRP

THey showed through in our new extension when the place was unheated during the winter - presumably condensation. As soon as we had the heating on they disappeared (and another layer of paint).

Is the room/house currently heated? I wouldn't bother with stain blocker - just paint it again...

JustAnotherSaver

The radiators are set to come on at 6pm & the heating is set to cap off at 16c.

there is a multi fuel stove there but i haven't lit it for a few weeks.

the room is approx 7m x 4m. It leads in to the diner where there used to be doors that separated but now it's totally open doorway.

With the living room being out of action we basically live upstairs & only eat downstairs for the time being.

So no it wont be the warmest of rooms.

prosaver

i had a problem with a water stain on the ceiling (leak from roof) ..tried everything ..but found that worked was painted over stains with a gloss paint waited till it dried ...a day and painted carefully with a silk elmussion (might be a bit steaky first coat) then waited till dried ..day again.. and another coat then it disappeared .

.good luck... let us know how you got on

JustAnotherSaver

I don't really want gloss going on there to be honest. I want a matt finish.

I was looking at the Zinsser Bullseye 123 or the 123 Plus as a possibility, but if it's no good then it's an expensive lay out.


Just had a look now & the marking is a little yellow. So i don't know if every time i paint it's going to colour the dabs.

Just re-read DRPs reply & are you saying that you would have to give it another layer of paint after each winter?

IF that's what you're saying then it's not the most ideal. Right now it'd just be a PITA, but once a carpet & everything is in it'll be a royal nightmare if that's the case.

prosaver

well try the gloss to seal it and paint a few coats with matt maybe 3?

prosaver

or you could put a undercoat (for gloss) after the gloss coat so the matt paint would hold and be less streaky , then a few coats of matt ..never tried it tho..trial and error as they say..

JustAnotherSaver

True

I'm just hoping someone has been in the exact same position & can say - i did XYZ and it WORKED.

I think our big problem is that the walls aren't 'normal' - they've been tanked & Sovereign says any coating can't be a vapour barrier as it'll be unsuitable. This rules out many solutions.

I've emailed them tonight to find out what they expect to happen if a vapour barrier paint is used.

Last resort will be wallpaper & a lot of heating i guess?!

prosaver

do you dry your clothes in the house..clothes horse?

JustAnotherSaver

Used to, but this was upstairs in the opposite corner.

Now they get done in the tumble dryer unless it's a nice day outside (rare i know).

prosaver

JustAnotherSaver wrote: »

Used to, but this was upstairs in the opposite corner.

Now they get done in the tumble dryer unless it's a nice day outside (rare i know).

try what i say see what happens ..nought to lose:)