Bricks blowing

[dog-man]

I am not sure if "Blowing" is the correct term, but I am sure that builders out there will know what I mean.

I have a very old house, (Victorian).

Just removed an old ceiling which needed renewing and noticed that the wall between the roof and ceiling has lots of bricks that have blown and are crumbling. Also looks like it could do with some serious repointing too!

Is there anything I can do to halt the bricks blowing?

What should I do?

I beleive that the previous owner neglected this wall, as it does get battered (on the outside obviously) by the elements. I have done some repointing, but still lots to do.

Rain used to get through this wall, but no longer.

Steve..

[Stuart Noble]

Then the blowing/spalling shouldn't get any worse

[Rich]

I have no idea whether this will work, but I suffer from the same problem and was recommended to wait until the bricks have dried out, then paint with them with a PVA/ water mixture to act as a stabiliser.

I'll report back if/ when I get round to it.

[dog-man]

Is there anywhere on the net I could look into this stuff?

Do you have a brand name?

And to the first person that replied saying that the spalling won't continue as long as I have stopped water getting through the walls.

Is that definite? I have definaitely done enough repointing on the outside to stop the rain getting in, although much more is needed to finish the job. (large wall)

Steve...

Rich wrote:

[dog-man]

I wonder if this stuff, watered down could be applied with a sprayer (garden type) rather than by brush?

Steve...

dog-man wrote:

[meow2222]

I expect someone will be rude to me for saying this, but to be fair to you I wouldnt be following the advice so far. Blowing or spalling is due to wet freeze cycles, the water content of the brick is too high for it to survive the freeze/thaw cycle undamaged.

The aim behind the solution is to reduce water content in the wall, to stabilise the bricks and to provide something other than the brick to take the brunt of any remaining freeze/thawing.

Steps to reduce wall water content:

if there is cement render or waterproof paint on the exterior, remove it if possible. But use real care, removing cement can cause a lot of damage to soft Victorian brick if not done carefully.

if pointing isnt upto the mark, repoint where neded, using 3:1 lime mortar. Dont use cement.

Check rain water goods to ensure water isnt running onto the wall

Check roof for leaks onto the wall

Use only porous finishes to allow evaporation of rain

Also you can stabilise the damaged bricks and provide a sacrificial layer for them by coating them with lime. Yes, lime lime lime. Maybe another day we'll have a thread on damp in Victorian houses.

NT

[dog-man]

After repointing, I will be applying Cuprinol Water Seal.

I am hoping that will help greatly.

I plan on reapplying it annually.

Steve.....

[Stuart Noble]

Lunatic

[meow2222]

thats precisely what you dont want.

NT

[meow2222]

idiot

[Shokka]

'Spalling'.

Has teh wall been repointed at any stage? If it's been done with cement based mortar that could be the cause of the problem. It should be pointed using lime based mortar.

shokka

[dog-man]

Is lime easily available?

I have never seen it in any of the DIY stores I frequent!

Steve..

[Phil L]

As others have stated, it's frozen rainwater (or more likely condensation if the outside bricks are not in a similar condition) which is/was causing the damage, my money is on condensation, aside from repointing the exterior, you could install a few vent bricks, this will increase air flow and allow condensation to evaporate more easily, also removing the insulation from between the two joists closest to the wall will allow a small amount of warm air to circulate up there in winter, once the wll has dried out completely (and it might take a few years) the insulation can be replaced.

[<me9]

B&Q have it in our local branch.

[The Natural Philosopher]

That actually isn't a bad solution (sic!)..it does slow down water absorption..so a splash doesn't get in..obviously long term soaking and freezing will bugger any bricks.

[The Natural Philosopher]

Its generally a combination of sodden bricks and frosts that causes spalling IME.

Heating the house and keeping it dry is all it takes.

HOWEVER once insulation goes in, the bricks get colder again..so externally treatment of very porous and exposed brickwork with a semi-waterproofing - simply something that sits in the pores where otherwise water might - should help.

In the final analysis, a wetherprof layer over the top may be called for. I happen to like smooth rendering, but weatherboarding is an option too.

[The Natural Philosopher]

Yup. remove anything that stops water getting in. This leads to a dry wall naturally.

No. The use of porous finishes and removal of waterproofing works not because it allows the rain to evaporate, but because most old houses had no damp proofing, and you needed to let the rising damp get out.

If you shove a cement render on an old building, the internal moisture, particularly with modern heating - no open fires to ventilate the place

- gets into the walls and can't get out, and the rising damp - especially if the walls are insulated and have a damp membrane inside of them, gets trapped at the wall base and upwards and since the brickwork is now colder (no heatloss cos is been insulated) the outside freezes and splits.

In short when you make major changes to the way a building is used, you need to consider the impact of these changes..insertion of DPC may be needed if insulation is envisages for example.

However, nothing beats a waterproof coating of render for keeping rain OUT of brickwork. The issues is, is that why its getting damp? If it isn't, then its as useless as a limp dick in a brothel.

Which you obviously only understand half of.

[The Natural Philosopher]

Don't worry. He is mostly harmless.

He has this bee in his bonnet about breathable structures.

Breathable structures are needed if they get damp in the first place. I have yet to see a vacuum packed brick spall ;-)

Follow your oen logic dog-man/.

Meow is a bit of a dick frankly.

[The Natural Philosopher]

dick.

[The Natural Philosopher]

Bollocks