The brickwork underneath our bay window is producing much white powdery stuff (salts?). Whatever it is is destroying the brickwork - the facings are falling off as shown in the picture. This is a problem that, to be honest, has been there for many years.
Is there anything - paint/treatment/coatings etc I can do to fix or at least slow the progress of this problem? Or is it a case of having the entire bay brickwork rebuilt? Thanks for advice about this
groundwater. I dont see any need to rebuild.
NT
Ah yes I thinkyou are right. There is damp on the inside of the bay too. There are two layers of blue brick as damp course and I get damp readings above that - but *not* on the eng. bricks themselves. The only way I can see how damp can rise above them is to do it via the mortar itself! Is this a known "path"?
Someone told me they've seen a diy treatment that can inject straight into the mortar - maybe that's what I should look for.
Even if this does fix it - the damage already done looks pretty awful (as per pic). I wonder if pebble-dash will hide i? :-)
The salts are down to water osmoting (?) outwards carrying sulphates with them. This is bad, because sopping brick will spall and split if it freezes.
So the salts and the damage are symptoms both of damp.
Once you have fixed the damp the salts will wash off eventually. Or pressure wash it, and repoint if necessary.
The bay window looks new. I would hazard a guess that its collecting and concentrating water somehow and the damp is due to bad guttering or similar.
Try and get some pictures of the highest pint where the efflorescence is starting. Chances are that's a clue as to where the water is coming from.
You must fix rte damp before you sort the cosmetics. But don't rush. Take time to establish what is causing it or you may do more harm than good. water sealed *inside* brick is worse than damp brick..
rising damp is normally unlikely to be the cause, and injected dpcs mostly a waste of time. I wonder if the salts have been in the wall all along, and a roof problem is leaching them out. Anyhow, as said you need to find whre the water's coming from.
Pebbledash - it'll look far better if you just replace the blown bricks. But forget cosmetics until the problem's sorted and the wall dried out.
NT
yes, although the engineering brick will carry some damp through (usually internally, which is why you're not getting a reading on the face of them)
Yep, you need to drill 10mm dia holes into the mortar joint 50mm deep and inject the DPC cream (it's like grease that spreads into the mortar bed) into each hole, and you need one hole per half brick (two per full brick) and it needs to be done on the same mortar course internally and externally
You can hide it with all manner of things, but stopping the damp should be your first priority, especially if you've noticed it inside the house also,
Also, if you have suspended wooden floors downstairs, you may want to check the joist ends in this location by removing some floorboards - it they are showing any signs of rot, cut out and replace, making sure you use a good preservative and rot killer on all existing and replacement timbers.
that method went out with the ark!
Normal B&D hammer drill and one 10mm bit
Normal silicone gun and a tube of DPC cream
Drill joints (easy), and as you correctly state, if access is only available outside, it will need double drilling, the thing is with the cream, it takes a few days to soak into the bed before you can drill through, but on a plus side, there's no expensive equipment to hire, so it doesn't really matter.
Its the plaster replacement that does the job on popular dpc injection jobs. There was a comany injecting nothing but water for a while, with no complaints.
NT
picture of that would be worth seeing.
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If damp starts low down and decrease as it rises up wall, then it could be as people are discussing rising damp .... if it starts higher up it will not be rising damp. Most cases turn out to be damp from other causes ... penetrating damp, form leaking gutter, ingress form a cill etc.
If it is penetrating damp you can inject a mortar based dpc solution under pressure ... it is solvent based (smells like white spirit) holes are dilled in mortar line every 450mm or so ... and you inject the prodcut under pressure... it spreads between holes causing a DPC barrier.
HSS hire the kit to inject (& drill) & the solution. if you do look at them get a trade card (free) it gets you 20% off first hire.
If your bricks are spalling ... i.e flaking off, they should be replaced as they will have lost the harder face, and will act like sponges to the rain.
could be, but in 99% of cases isnt, so its not where I'd look until other possibles have been ruled out.
Or you can simply use gravel. Dig a small trench 2 or 3 bricks deep around the outside of the wall, filling it with gravel as you go. Don't dig down to the base of the foundations!
But really the op should search for and remedy any faults before contemplating any of this.
NT
A few years ago we had (fell for) the damp course injection treatment. The eng bricks were drilled all around the foundations and injected. It seems to improve things - but now seems to be coming back (big sigh).
Thanks for all the suggestions as is all a bit stressful trying to find out what the heck is the problem.
I found this
Dryzone is what everyone uses now, but you don't have to pay 64 quid to do it - I bought a tube last week and it was less than 20...also the gun/applicator can be hired for about a fiver a day.
Noted your earlier post with interest and found this outfit after searching for "DPC cream":
Yep I've used permaguard before, they're pretty much all the same. If your walls are 18in solid, they willl be four bricks thick, this means you will have to double the meterage quoted on that site
In article , Phil L writes
This is a new product to me, thanks for the intro. Looks like there's a better chance of proper application due to the absence of risk of fluid leaking out under pressure. Both sites seem to have good info on metering for thick walls, I imagine that old properties with thick walls and no dpc are a common target for treatment.
Thanks again - that looks to save me a lot of £ - I could just do it and see if it works.
There do seem to be a lot of different types of products. I need to do some reading to know which one to get. Any (further) tips much appreciated.
somewhere. Then the white is from salt in the sand as someone said.
But chekc gardeners havent composted the garden outside higher than the damp course.
]g]
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