Hello, new member in great need of help...

[annec]

Hi - is anyone able to advise us about this awful ongoing problem please? There are a few areas in our house, mainly on external walls, where we have a persistent problem with bubbling and furring paint. It first occurred about 6 years ago, before we had K-Rend and cavity wall insulation (the bead type).

 

We've looked extensively into this and it seems that efflorescence is the problem. Unfortunately, nothing we've tried seems to work - this was my fourth attempt at trying something else but the same problem continues. 

 

I've used damp-stain paint, vinegar, PVA and undercoat but every outcome is the same. The walls are ruined with constant sanding, scraping and overpainting and I'm at a loss as to what to do next.

 

I've read that salt neutraliser treatment will prevent salts recurring but only if the underlying cause of the problem has been fixed. I suspect the underlying cause is salt in the brickwork but we have no way of gaining access to it.

 

I've not yet tried Zinsser because I didn't know which Zinsser product to buy and not sure it would make any difference?

 

Would lining the wall with paper make any difference? Would it happen the same on silk paint (we have matt)? Does anyone have any suggestions as to what to do next - please? We're getting desperate now. Thanks for reading.

 

[SteamyTea]

Welcome.

Have you checked for leaks/cracks on the outside?

Downpipe and gutter problems as well.

Also is it possible the roof has failed and water is getting in there, then finding a path to the wall.

What construction type is your building?

Edited October 5, 2021 by SteamyTea

[epsilonGreedy]

It looks as though you are trying sticking plaster solutions when instead you need to identify where the excess moisture is coming from. The water is either getting in from the outside or lack of ventilation is not allowing normal internal air moisture to escape outside.

 

A few external photos of that room will help the many experts here guess the source of your problem.

[saveasteading]

What is on the other side of the wall?

You say it is an outside wall, so could we have a photo please, even if you don't see any issues there.

All the wall from ground to roof.

[markc]

As above, forget what you can do on the inside, first look to sort the problem, then fix the effect

[Big Jimbo]

That plaster looks very wet. The only time i have seen a problem with the salts in brickwork leaching through plaster, it caused a dry spot that brought the paint off, not a wet spot as yours looks like.

[annec]

Thanks both for your replies. I appreciate your interest and agree we're trying sticking plaster now - after several failed rescue attempts.

 

Steamy Tea - the house was built 1891 and is close to the sea. It's basic red brick, now covered with K-Rend. 

We have no leaks/cracks on the outside, no downpipe and gutter problems, the roof has been recently repaired where it was affecting a different bedroom, not near this one. The roof was mostly re-roofed when we bought the property 8 years ago.

 

epsilon Greedy - I don't think it's water getting in and there isn't a lack of ventilation that I'm aware of. We have the same problem in four other areas of the large kitchen/lounge area on that external wall, below this bedroom and the next bedroom above (which isn't affected). 

 

External photos attached.

 

[annec]

saveasteading, markc and Big Jimbo. Thanks for all your replies. The plaster isn't actually wet - that's shiny PVA and staining from using a brush to apply it. It's never been wet inside - only bubbling and furring. 

 

I've attached external pics to show the area affected. We can't get to the brickwork.

 

My husband has completely renovated the house and not spared on materials or time. Everything has been done to a high standard, including raking out the cavities downstairs before rebuilding/renovating.

 

The chunks out of the stone sill were already there but do not allow ingress of water anywhere.

Edited October 5, 2021 by annec

[nod]

It has to be coming from above 

Possibly blowing under the slate or tile 

Whilst K Rend is breathable There’s to much there for it to be soaking through the cavity Roof is the main suspect 

[Big Jimbo]

As the Drifters would say. I would be looking "Up on the roof"

[annec]

Thanks nod...it seems that most people are suggesting that it's water ingress from the roof. However, the other main problem areas are actually at ground level and in five different areas of a big kitchen/lounge - far apart from each other and spanning two rooms.

 

If it was water from the roof then I'd expect there to be more problems on the first floor but there is just the one bedroom affected in that corner. We also have a second floor and there are no problems at that level. 

 

None of these problem areas are wet or damp - totally dry but bubbling/furring on the surface, some deeper than others. I'm really confused because there's no water anywhere and we have recently had roof repairs done on that side. The problem we had was rain leaking in the corner of another bedroom but that's completely sorted out now with no further issues.

Edited October 5, 2021 by annec

[SteamyTea]

Water takes the path of least resistance, so can come out in the most unexpected places.

[Mr Punter]

Hi @annec and welcome.

 

Just to recap:  The house is 140 years old.  You bought the house 8 years ago and 2 years later paint began to bubble and fail in several areas of the house.  The roof was mostly replaced 8 years ago but you have had further roof repairs.  At some stage after the problem emerged you had CWI installed and the outside rendered.

 

A couple of observations from the photos:  The plaster does not look original.  Nobody replasters for fun so it may well have been to cover existing damage.  Your second roof photo shows very little overhang on the tiles - either at the verge or the eaves.  This makes it much easier for wind driven rain to find its way in to the top of the wall and down the cavity, where it is now less able to freely evaporate.

 

It may not feel damp indoors as it is nice and warm and will evaporate away.

[annec]

Thanks, Mr Punter, the recap is correct.

The house has been completely renovated and every wall stripped back to bare brick. New plaster was applied in every room.

I agree about the lack of overhang.

[TonyT]

Find someone to do a speedy carbide test.

 

https://www.michaelparrett.co.uk

 

Check for leaks

check for ventilation 

check breathability of products

 

 

[TonyT]

Gypsum plaster over existing lime?

do you have kitchen/ bathroom fans or other means of mechanical ventilation/heat recovery?

 

[TonyT]

Cold bridging of external stonework all the way to the blistering paint area?

 

Best Buy some humidity/ temp sensors for the rooms to start recording data, these can be bought for about a £5 or less on line

[annec]

Thanks so much Tony T - this is an avenue we need to explore further. Your points are helpful.

 

Gypsum yes, but all walls were stripped of old lime plaster back to bare brick, although the pointing is the original.

[ETC]

Sounds like the walls are drying out into rather out of the building due to a sealed wall or lack of ventilation causing condensation. Try ventilation and/or an isolated metal stud internal wall.

 

[SuperJohnG]

I had this issue once, old cavity wall house we had insulation blown into the cavity then I jad a recurring issue where there used to be a fireplace it had no damp but I was getting  effervescence through new plaster in the end we used a specialist salt treatment which was painted on and solved the issue.

[saveasteading]

Good pictures thanks and tidy work.  I had expected a scabby old wall.

I agree that the first suspect is the roof overhang. In heavy rain the water will chute into the gutter, and probably work ok. This is easy to check but you will get wet looking.

in gentler rain the water is likely to 'curve' back towards the wall as it dribbles over the edge, and may miss the gutter. Then it may run onto the wall and in. it doesnt take much water to create a lot of damp.

 

If that is the case then there may be an easy solution, just tucking felt under the tiles and into the gutter.

 

Do please stand in the rain and see what you can see.

 

[Temp]

15 hours ago, annec said:

 

I've not yet tried Zinsser because I didn't know which Zinsser product to buy and not sure it would make any difference

 

I agree with others about trying to find the source. I suspect a roof or gutter issue but you say none of the upstairs rooms are affected?  Is any of it below an upstairs window? Certainly looks like a water issue because the problem areas appear to form vertical bands in the photos.

 

I've found Zinsser paint very good. Had lot of issues with paint coming off ceiling above a shower. Flaking and powdery patches. Zinsser worked a treat. I was lazy and didn't paint the whole ceiling and you can clearly see now where  the zinsser ends as we have a little mould after that point. Will be doing the rest of the ceiling.

 

I've used the Zinsser Bulls Eye 123 primer with their Perma White interior over the top.  Think I would try the "Bulls Eye 1-2-3 Deep Tint Primer" on its own on some of your problem spots. See if that survives before doing larger areas. 

 

 

[Pocster]

15 hours ago, annec said:

Thanks so much Tony T - this is an avenue we need to explore further. Your points are helpful.

 

Gypsum yes, but all walls were stripped of old lime plaster back to bare brick, although the pointing is the original.

I know everyone suggests the roof / gutter as an issue . Yet the wall looks very clean . Had exactly the same internal issues you have . Checked outside including the guttering - nothing obvious. Then one day whilst passing by it was p*ssing down - then I could see it . I’d certainly go outside when it’s hammering down just to check .

[Ferdinand]

Points not raised.

 

Writing as a small landlord...

 

One cause may be that the render makes it more difficult for moisture to escape, and so moisture tends to hang around more. I note that your 2G windows do not seem to have trickle vents, which will have helped seal the house even more compared to how it used to be.

Useful test: What is the humidity in the house like? If it is high (which means perhaps 65-70% or above, ideal is 50-55%), that suggests that ventilation may help. You can get min/max humidistats/thermometers from Amazon for £10. I have about 3 of these:

https://www.amazon.co.uk/ETI-Ltd-thermometer-hygrometer-indication/dp/B017KNQNZA/

My only warning is that they don't bounce off tiled floors.

 

Do you have any lifestyle habits that would cause problems - eg drying washing inside, tumble dryers that vent to inside, bathrooms without decent ventilion etc? Find alternatives.

 

My best anti-moisture measure to make my rentals more resilient to tenant lifestyles is to fit a PIV loft fan, plus a constant ventilating HR fan. That maintains a slow throughput at minimal cost. I also do things like fitting small shelves immediately over all the radiators.

 

Examples would be:

This: https://www.nuaire.co.uk/product-list-page/drimaster-eco-range?v=DRI-ECO-HC

and this: 

https://www.vent-axia.com/range/lo-carbon-tempraselv

 

That has been my policy for a decade now, and it works ime.

 

While you are at it, make sure all your fans have anti-backdraft shutters.

 

F

 

[Ferdinand]

One other thought is do your gutters overflow in heavy rain?

 

(Solution might be deep flow gutters)