What causes bricsk to deteriorate?

This is an ad from Facebook. Someone offering a service to fix dodgy supports. The thing that got me was the actual state of the bricks. With bricks being well protected from the weather under a house I thought they would have lasted way longer than any other brick in the house.

I contacted the guy, who said it could be moisture or poor workmanship or groundwater.

I think this is amazing. Bricks should be tough enough to withstand moisture. We build bridges from them, tunnels, line river banks. Even multi story buildings are built from bricks. It's quite shocking, really, to see this.

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What happens is that in ground with high salt or mineral content and there is no dampcourse in place the bricks wick up the moisture and then when they dry out you are left with the salt that crystalises and causes the bricks to frett and spawl. This happens with other masonry like sandstone and terracotta tiles as well, you will often see it around swimming pools or seaside masonry which is why they use a penetrating sealer to stop the water penetrating the surface

Brick manufactures note in their brick range which ones are salt safe for those types of conditions

That's some serious damage.

Looks like the adjacent piers have been repaired, but unfortunately it will continue unless the rising damp is addressed by completely rebuilding the piers, installing a damp course barrier and using suitable bricks to rebuild as Beardy mentions. Makes you wonder what is happening below ground.

It's perhaps a good time to have a look at site drainage and underfloor ventilation as well. Those issues don't happen in isolation, as there usually are other site issues compounding the problem.

Oh, and bricks like most building materials are manufactured with properties to suit specific applications. Other issues such as incorrect kiln firing or a poor batch of "clay" can also affect long term durability.

A lot depends on the quality of the bricks and their firing.

Porous bricks will take up moisture, then if you have freezing temperatures overnight the water will expand as it turns to ice breaking the brick in the process.

Good information. Thanks. And the concern is that it's out of sight and out of mind. Probably the first clue would be the floorboards squeaking or gaps appearing under the skirting.

Fixing it in the example shown in the photo would be awkward. A small demolition hammer would be helpful in digging holes for the footings. You'd still have to pull the loose material out manually. The real trouble would be where the underfloor space is impossibly tight, as is sometimes the case.

I think your contractor fellow was right. Looks like you got some shoddy bricks there.

Honestly, they look more like red cement blocks than actual kilned bricks. People did that to save a buck... As you see, it looks mostly fine higher off the ground.

Proper bricks are bonded via vitrification at high temperatures, meaning the particles melt and fuse together. Cement blocks use the lime to encase the aggregate in a hard lattice via chemical reaction. Moisture + Acidic pH/salinity/very caustic pH + cement blocks = mush. You can get cement which will survive all of those things, but it's often not cheaper than decent bricks.

EF

House bricks are usually either "pressed" or "extruded." The former are the old style bricks with a frog and not seen so much today. They are relatively soft and added to that there are seconds also, which are typically used in non visible areas under the house and are classified as seconds because they were not fired so hard.

The extruded bricks are much, much harder and normally have holes through them. Three large holes or ten or so small holes.

The bricks in the pic look like pressed bricks and could also be seconds. In conjunction with adverse minerals in the soil or expansion and contraction while wet, they have resulted in that condition: Not something I have seen before. Pressed bricks have to be wetted down before they are laid as being porous they suck the moisture from the mortar if they are dry. This gives some idea of how prone they are to moisture.

Regards
Paul

As Beardy said, it's efflorescence gone mad. Cyclical wet/dry conditions make the brick work like a wick and the mineralised water crystalizes in the brick/cement. The crystals being larger than the solution force the surrounds apart like a tree root in rock.

Google brick fretting and you will find lots of examples of this happening. You see quite a lot of it in beachside brickwork

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Originally Posted by Beardy

Google brick fretting and you will find lots of examples of this happening. You see quite a lot of it in beachside brickwork

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Also look at concrete "cancer" in saline environments.

Both brickwork fretting and concrete "cancer" are strongly linked / correlated not only with beach side areas, but also to tradesmen, and or builders / developers cutting corners on materials, using 2 nds bricks, poor mortar, or a concrete mix not specified for the application. Have a look at the number of new unit complexes across the country with serious structural issues.

Another case of "Oils ain't oils, Sol." the bricks look like bricks ..... but that's about it.

In the OP's image and situation a concrete pier or steel column, may not have faired any better. I would be looking at site drainage issues and correcting them as well as performing the repair / replacement of damaged piers.

Buildings do require regular programmed or preventative maintenance to minimize damage and to prevent issues becoming so advanced that they become a structural hazard.