Damp question

[martinbyrne56]

Stuart, please see the trade lit below. I have used this sytem to water proof a brickwork viaduct in London and 18 months later the arches are still dry and let out to tennants without a problem. Things have moved on from micro porous paints. Through my work with London Underground maintainers Metronet Rail, I have seen the use of these products grow quite quickly and are now being introduced as standard to new build and maintenance works. The worst product for external masonry is a surface sealer as it cannot protect against freeze thaw and transmission of vapour through the substrate.

Chem-Crete SofiX CCC700 is a unique one of a kind water-based crystallisation product specifically designed to permanently block moisture and vapour transmission in concrete or masonry structures up to 16 lb./1000 ft2/24 Hours. Application of the SofiX CCC700 system blocks moisture and vapour movement through concrete and masonry substrates within 24 hours. The Chem-Crete SofiX CCC700 can be easily applied by spraying or rolling. Chem-Crete SofiX CCC700 is designed to be applied to concrete substrates that are 7 days or older. The Chem-Crete SofiX CCC700 is formulated to enhance deep penetration into the concrete substrate through capillary action. The product components migrate deep into the concrete substrate while reacting to form a hygroscopic and hydrophilic crystalline material which permanently blocks the concrete and masonry substrate pores. Even under the influence of constant hydrostatic pressure, the crystallization continues to fill and block the migration of moisture through the concrete substrate. The crystallisation activity of the SofiX CCC700 system is continuous while moisture is present. The product becomes inactive during dry conditions and is fully reactivated when moisture or moisture vapor are present. The unique "reactivation" is the key in providing permanent waterproofing protection for any concrete or masonry substrate. Chem-Crete SofiX CCC700 is an odourless, colourless, clear liquid with very low viscosity that allows it to penetrate deeply into a concrete substrate or other masonry products. The product protects, preserves and waterproofs without any surface film formation or colour change.

[meow2222]

snip explanation

Better than Stuart's approach, but dont you think the best bet is to just let the building work correctly in the first place? The great majority of damp old buildings are damp because they have been modified inappropriately, whether by accident or intent. Common causes of damp are blocked underfloor vents, external cement render, cement pointing, use of masonry paints and so on.

Some certainly are damp by design, but theyre are a very small minority imho. The problem is simply the general lack of understanding how old buildings handle damp, leading to suggestions like trying to waterproof the wall, and explanations like 'the bricks are porous.'

Lack of maintenance is also a common issue, sometimes causing penetrating damp from blocked gutters and downpipes, rusted through downpipes, blocked drains etc.

NT

[Guy King]

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Or - like our old house in Hounslow - the environment was soggy. I once lifted the downstairs floorboards for something and the soil beneath wasn't just damp it was wringing wet. Glad we only rented it!

[Stuart Noble]

Sounds like silicates. Hardly new, and hardly unique. But, if you've used the product and it works, it has to be taken seriously.

[Stuart Noble]

The great

So I wonder which category this railway arch comes under. If these products prevent the passage of water vapour, how come you're not predicting disastrous consequences?

[martinbyrne56]

[Stuart Noble]

Given that these products are supposedly able to prevent the passage of vapour, and therefore render the building hermetically sealed, the conservationist taliban view is that the moisture generated by human activity inside (yuk!) will not be able to escape. All stuff and nonsense because in reality nothing comes close to a total seal on masonry.

I suspect silicates would reduce the porosity, and may well be the best solution for bare brickwork. I'd be interested to know whether the bricks have changed visually in your railway arch. Were they cleaned first? Any photos anywhere?

For those stuck with painted bricks or, worse still, painted render, a surface coating is still the only option. In this case, solvent based masonry paints are IME the only products worth considering.

IMO you do whatever you need to buildings to make them habitable. We need healthy young families with a roof over their head. We're not running an architectural museum here.

[martinbyrne56]

The arches were brushed clean and blasted with compressed air to remove the finest particles. This is all the budget would allow for as jet washing etc was too costly. However, we have research on the product uses with differing preparation methods, and there is no difference in Sofix performance between jet washing and brushing.

There has been a slight darkening of the brickwork, but it is consistent throughout and does not look false. There is not surface finish like a sheen or gloss. I will dig some photos out and attempt to post them. Not too sure how to do that.

I still stand by my point that sealing the brick face is by far the worst thing anyone can do to brickwork. I cannot understand anyone specifying it for any work of significance.

[meow2222]

That isnt any big problem, and doesnt preclude a dry house.

NT

[meow2222]

It always puzzles me that you persist it making no effort to understand the subject.

NT

[Guy King]

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Except it made the whole house feel damp and smell musty. I know it could have been fixed - but since it wasn't ours and we weren't planning on staying ICBA.

[Stuart Noble]

I suspect you find anyone who disagrees with you puzzling.

Please tell us why you find the products under discussion preferable to a surface coating, given that they allegedly act as a total seal against vapour. I thought breathability (aka putting up with damp) was the cornerstone of your theory.

[Stuart Noble]

I totally agree, but this is purely academic since surface coatings are unable to form an effective film on masonry. They soak in instead. The clear repellants marketed by Sovereign Chemicals and others are based on siloxanes which, as I understand it, penetrate in much the same way as silicates without forming a film of any kind. Whereas silicates are basically tiny particles of sand, siloxanes are greasy/rubbery. Both are said to move about in the masonry in response to water. Yes the photos woud be interesting but I think I can visualise the "wet" look you mention. I expect there's a way to put them on the web for free so that anyone can view them without invitation. You could use the web space from your ISP but all that ftp stuff is a bit of a pain.

[martinbyrne56]

If you are using Pavix you get a very clever product which is much more than a simple seal. The material is a hygroscopic solution that applies hydrophilic and hydrophobic actions. It seeks water and combines with it to grow crystals that resist water. The crystals, which adhere tightly to the concrete pores, grow and shrink according to the amount of available moisture. Consequently, the impregnate provides water-resistance and reduced vapour permeability according to the prevailing conditions. As Pavix is an impregnate, it cannot be damaged or broken like a traditional seal.

Yufix is similar to Pavix, that is they both stop water penetrating into the face of the brickwork, but allow water to pass through to the outside. As neatly summed up earlier as a Gortex jacket for brickwork.

Sofix works in a slightly different way and prevents water passing in either direction.

In my ( and a growing number of infrastructure owners) opinion, environmentally friendly and integral protection provided by such products is preferable to the "off the shelf" product available at B&Q. The protection and preservation of heritage assets is tightly controlled by English heritage etc. They categorically refuse to allow any heritage assets (such as war memorials, grave stones etc) to be sealed with a silicon sealer. However, products with the attributes of the above are acceptable following a period of proving. So far, the largest project for Yufix is the preservation of Mt Rushmore (currently ongoing). They will not be using Thomsons Water Sealer for work like this. Just because it is new or innovative, don't be scared or dismissive. Try to embrace progression.

[Chris Bacon]

Repeated coatings form a film, though (cf. painting MDF, cut kitchen chipboard worktops, etc).

[meow2222]

Its a question of being realistic Martin. Some new building materials and methods have problems that only show up many years down the line. Many miracle treatments have been and gone, causing one problem after another, and failing to resolve the problem. Despite over a century of progress in damp technology, the original Victorian method of handling damp in old buildings has proven over time to still be the best, despite the technology's considerable age.

Perhaps your new wonder chemical really is wonderful, but I cant help but notice 2 things worth bearing in mind:

1. Almost none of the new wonder damp cures in the last century have proved worth adopting, despite often looking good initially
2. Damp treatments dont resolve the cause of the damp, and if the cause is resolved, there is no need for such treatments anyway. Their fundamental flaw is that they just dont address the point in >90% of damp cases.

Truth is its a hard life when youre in business with these kind of products.

NT

[Stuart Noble]

I think maybe it's time you revealed what you think the cause of damp is in >90% of cases.

[Stuart Noble]

It isn't just a question of Sofix/Yufix/Pavix vs Thomsons Waterseal. Silicate and siloxane based products have been around for a while and, to my knowledge, no water repellant has ever been based on silicon. I'm sure your products work very well but the claims that they're new or unique I would take with a pinch of salt. You're not the UK agent by any chance?

[martinbyrne56]

Nobody would deny that we must treat the cause not the sympton. But if your cause is damaged Victorian waterproofing which happens to be integral to the structre (such as a bitumen lining to the top ring of the arch barrel) then you are not in any position to reapply that coating. What we must also consider is that in 99% of cases of damp treatment, the client is going make decisions based on cost alone. Performance is secondary as he knows he will get a product to treat the symptom and he is unlikely to want the disruption or cost of treating the cause.

Obviously if you are talking about Buckingham Palace then you will do a pucker job, but for average Joe, he will want an effective quick win, which can be monitored and managed over time. Cost will always force the issue.

I wish I was the UK agent. That job has gone to either ASI Ltd and PCIS Ltd. I am only telling you of my experience of Engineering Heritage and my time as a civil maintenance engineer.

[martinbyrne56]

I shoujld have included this in my last post. Silane based products are on the decline. It is too costly and dangerous to use. The PPE for apllicators and protection to the public every time you open a jar of the stuff means that clients such as Londonon Underground and the Highways Agency have banned its use. In fact, the HA have re-written their standards exclusivley for the use of Pavix.