Using Remmers, or similar, modern, breathable waterproofing treatments on period brickwork

[Marcus Read]

Hi there.

 

We've bought a huge 'project' house. It's a Victorian red-brick house, which has never been repointed since the house was built in 1880. We are currently cutting out and replacing hundreds of hollow/spalled bricks, and will be repointing the house with hydraulic lime mortar. We live by the sea and the house has to endure lots of wind and rain. The bricks are red-rubber style handmade bricks and are obviously quite soft, give how many had deteriorated.

 

Our specialist pointer has suggested we apply Remmer's microporous one-coat façade cream to the brickwork after repointing, as it's breathable and will help the bricks repel water and may inhibit further deterioration in the future. Given the huge cost of the repairs, we're obviously keen to do anything to try to make our repairs as permanent as possible. On the other hand, we have had other professionals tell us not to treat the bricks with anything, as they are are meant to get wet, and then dry out, but that a weatherproofing treatment can trap moisture inside the brick and this will actually accelerate their deterioration. Ah... says our pointer, but they're talking about older treatments, which do not breathe and that this problem does not arise with Remmer's or similar new breathable treatments. 

 

Do you have knowledge in this area, and what would you recommend? 

 

Many thanks, Marcus

 

Edited March 3, 2022 by Marcus Read
typo

[markc]

No experience with the treatments you mention but yes, bricks are porous and soak up water. If you weigh one and then submerge it in water for an hour or so and weigh again you will be surprised how much water they take up.

if fully sealed I can’t see a problem, but if water does find its way in and then can’t get out and freezes you have the spalling all over again

[Ajn]

1 hour ago, Marcus Read said:

Do you have knowledge in this area, and what would you recommend? 

Our building was 1820. We recovere quited a lot of bricks from the heated walled garden wall (planning issue not our requirement to remove it) to use as replacements and the builder did turn a few around. He had not used any of the newer treatments so didnt want to use anything that would seal the bricks given that A) it wasn't that bad afer 200 years and the new lime pointing would keep the water out. B) most of the damage was around areas that had been repaired with gypsum based motar C) Lime needs quite a while to get to its final state and what effect would a breathable sealer have in that process.

 

The building itself still needs to breathe. So we did nothing and a year and a half later no sign of any problem.

[Marcus Read]

Thank you. These are both interesting and relevant replies. In the case of Ajn, the only thought would be it's a bit too early to know for sure. Shame you can't have two houses, one with and one without, to see. And in the case of Markc, yes, it's the freezing trapped water that is that I was warned about, but the guy assures me that this does not happen with the new, breathable treatments. I'm tempted not to treat the bricks, as it's a bit of an unknown quantity. But will keep mulling it over, till time runs out... and keep looking for answers here. Hopefully, I'll also get an answer from somebody who has used this product and has some feedback on their experience. Thanks again.

[Gone West]

The only comment I can make about this is that I used a silicone based treatment on a solid brick walled Victorian cottage back in the nineties. I thought it was breatheable but I may be wrong about that. It worked well with water beading off and I lived there for another twelve years without any problems.

[joe90]

I have treated my west facing (new) brick wall as it catches rain from the Atlantic and the first winter it was saturated , since treatment rain water runs off it like glass and yes it’s breathable.

[Marcus Read]

Very interesting, thanks!

[crispy_wafer]

15 hours ago, joe90 said:

I have treated my west facing (new) brick wall as it catches rain from the Atlantic and the first winter it was saturated , since treatment rain water runs off it like glass and yes it’s breathable.

What product did you use @joe90 , We built in slightly angled brick cills (i think like yours?) and was thinking of protecting these as they may have more moisture than normal running onto and off

[SimonD]

23 hours ago, Marcus Read said:

it's breathable

 

As a general rule, check directly with any manufacturer. Vapour diffusion is typically indicated using an SD value or similar. Ask the manufacturer for this value and test results before putting anything on your wall.

 

From the looks of it a hydrophobising 'creme' that Remmers make is called Funcosil FC. In the technical data sheet it says

 

Quote

Water must not be allowed to penetrate behind the hydrophobized zone.

 

It says it

Quote

Enables water vapour diffusion

 

But this is a pretty meaningless term and there is no Vapour diffusion test value.

 

I'd be approaching use of this with great caution.

 

A quick net search throws this up which does provide test results and certificate

http://www.stormdry.com/articles/breathable-damp-proofing-for-older-buildings

 

But still, it's worth bearing in mind how long the existing masonry has lasted and thus how long your renovation is likely to last without treatment under those harsh conditions. It seems to have done pretty well under the circumstances.

[joe90]

2 hours ago, crispy_wafer said:

What product did you use @joe90 ,

Kingfisher extreme climate, recommended by my builders, not cheap but I found it very good and easily applied by brush.

[Marcus Read]

Thank you for the really interesting replies I have received to this thread.

 

I am also interested in what SimonD has written, including the link about the Stormdry treatment which seems quite similar.  But even Simon ends by cautioning whether it is worth applying this to a period property that has survived the elements for 140 years and has been built using materials that were designed to get repeatedly wet and dry.  Moreover, the house despite its build-date of 1887, surprisingly has got cavity walls, so the outer skin getting wet does not seem to be causing any significant dampness indoors even in its currently dilapidated condition.  Nevertheless I am still thinking about it…

[joe90]

37 minutes ago, Marcus Read said:

to a period property that has survived the elements for 140 years

However 

On 03/03/2022 at 10:30, Marcus Read said:

We are currently cutting out and replacing hundreds of hollow/spalled bricks,

Perhaps if they were treated this would not have happened 🤷‍♂️

[Marcus Read]

Thank you, Joe90. Therein lies my dilemma.

 

I am tempted by such a product due to the proximity of the sea and the sheets of rain that beat down on our house regularly. However, many people have told me never to seal period brickwork and that moisture will find its way behind and cause untold damage moreover hydraulic lime takes years to cure and the process of getting wet is part of the curing process. I am worried that a sealant might be good for the bricks but compromise the way the hydraulic lime mortar works.

 

On the other hand, there is Joe’s 90s comment about the large number of spalled and hollow bricks. Much of this is due to the soft (red-rubber-style) nature of the bricks themselves and the birds pecking at them for their nests, but some of it must also be due to the repeated action of frost on the surface-layer during cold wet winter month, hence I am still considering the matter…

[joe90]

26 minutes ago, Marcus Read said:

hence I am still considering the matter…

Good, perhaps consult a specialist in lime and/or period properties!