Confused by what i think is salt on interior wall

[Ricardobles123]

My partner and i have been dealing with a number of issues with our property. Perks of buying an old home that wasnt looked after i guess.
In our living room on the gable wall we have noticed the following appear on the gable wall. We have a fireplace where there was an old wood burner, we removed this and had the old chimney stack removed and the roof covered at the top.
(Chimney breast has not been removed as we plan to put a new woodburner in later next year)

If it wasnt obvious already im fairly clueless when it comes to these things and the large amount of differing advice and opinions ive read online and scare mongery from "damp proof" experts etc has left me non the wiser.
Hoping someone here has encountered something similiar and has some advice.

Pictures attached

 

[Matt Green]

It's efflorescent salt crystallising as water is drawn into the brickwork and evaporates back out again leaving the salts behind. Fireplaces that have burned coal get their brickwork infused with hygroscopic salts that draws water in dissolves salt and leaves it on the internal surface when the water moves back out into the warmer air. It's a fairly common occurrence and is specifically excluded from damp-proofing guarantees.

In terms of doing something about it: how do you feel about bare brick as an internal finish...?

It's going to take a few years for all the salts to move out, but they will do eventually. Alternatively, there are salt retardant plasters available and re-plastering with anything 'normal' is going to cause it to drop off (which might be a sacrificial option for you as long as you expect it to happen and budget for re-plastering in a few years time). Re-plastering in lime would see you brushing salt off for years but might look slightly better than bare brick.

M

 

[Ricardobles123]

Thanks Matt, really appreciate you taking the time to get back to me. As i stated I dont really know too much about this but i think a good first step is stripping it all back to brick and see what we are working with. Im all for the brick internal finish, my other half... not so much. We were going to go down the route or ripping everything down to bare brick and looking for some sort of treatment for it. But i assume nothing like that exists so the salt retardant plasters might be a good option then.

For context the chimney breast splits into 2 from the dining room and the living room both rooms share the same gable wall and have this issue in different areas.

The living room had a woodburner with a flue liner and the dining room being an old gas fire which doesnt seem to have any liner whatsoever. At this point the old gas has been disconnected and eventually will just be bricked up and an electric fire put in its place. Living room will be having a new woodburner put in once we get the rest of the room sorted.

 

[WetWales]

Interesting thread,
We’ve recently replastered our whole house in lime, base coat eco cork the. Lime skim.
the kitchen wall is still drying out, still damp patches after roughly 2 months, now showing salt deposits on a few patches

Other side of the damp wall is an old lean too - it had a higher ground level with steps down into the lean too, we dug away external ground level but left the steps and I think these higher steps have led to no air flow and the resulting wall inside lean too was green with algae growth ,
I washed it all off vigourosly with bleach, brush and hose and dug out the steps to ground level and now airflow to outside

When cleaning the wall of green stuff I found a fair bit of coal in between the stones, coal dust i stead of mortar and some large pieces so I assumed they used the lean to for coal storage as well as farm dogs, found animal bones and chains too!

My question: would the storage of coal against the outside of the kitchen Wall for many years so the coal dust has worked its way into the wall, would that be enough for the salts to get drawn thru to the inside and come out my new plaster?!

I’m just going to brush it off and see how it goes, hoping as the wall dries I’ve the months and once ufh is on,


more jsut curious really as to where it’s coming from, we’ve even lime
Plastered inside both fire places and so far nothing has come thru!

 

[Cubist]

would the storage of coal against the outside of the kitchen Wall for many years so the coal dust has worked its way into the wall, would that be enough for the salts to get drawn thru to the inside and come out my new plaster?!

I wouldn't have thought so. My understanding of the chemistry suggests that the coal would have to be burned to release any salts it may contain before these accumulate, typically, in the chimney. Heat and water can then aid these salts, and others accumulated from the masonry, to migrate to external surfaces. Coal dust though is extremely fine and can be carried quite easily in the air and any water to appear in some very odd places in the vicinity. Not to mention the lungs of many miners sadly.

 

[WetWales]

Ah that makes sense I suppose that it has to be burned to release the salts, someone must’ve been burning halfway up the dairy wall in years gone by!
There’s also a small patch of concrete around the pipe that they used for the cooker hood and the damp patches correlate with the concrete patches , but 6inches below, so Lower down but I’m thinking maybe the concrete is trapping the moisture and it’s going down and out inside , getting sucked internally and out

Who knows, just hoping it will keep drying!

around us it’s slate dust and silica that would’ve been the problem down the mines, equally as bad for the lungs and during this renovation I’ve seen the different approaches by trades people, lime plasterers, experts in slate and ourselves to masks, holding breathe etc etc

 

[a twig]

I ended up with salts on a first floor window reveal once - still no idea what caused them but they stopped after a few weeks