The humble brick, that wonderful hand sized polyhedron made from nothing more than fired dirt, which has built everything from Roman aquaducts, to castles, to your outside privy; what a wonderful thing it is. I can’t understand why peoples’ eyes glaze over when I mention my brick collection, or why they remember all sorts of pressing appointments and leave when I offer them a tour. Even some other architects find it strange, but they tend to be from the glass, steel and concrete faction.
It makes me want to weep when I see poorly laid or badly repaired brickwork. It’s only too common, unfortunately.
Picture the scene: a woman opens the door to a rough looking man who has just stepped out of his unmarked white Transit – ‘Your house needs pointing, luv – you don't want damp walls! I’ll do it for you – with the real thing, cement and none of that dirty old lime mortar’. She agrees, of course, who wants damp all over their nice new stencilling? After discussing it with her husband, who becomes worried about his perfectly good, if old, brickwork, they agree to pay the exorbitant cost.
Two weeks later, the damage is done, and the brickwork is now traced with the sharp, hard, ruled lines of blueish cement mortar, with added splash marks and a stain on the patio where the cowboys have mixed the wretched stuff without putting some protective boards down. Cement mortar is very hard, sets quickly and is made from Portland cement. You can buy it in little bags from B&Q and it is a grey blue powder. Mix it with water and sand and Bob’s your uncle – a wet, sloppy substance which the cowboy builders swear by (among other nasty things).
Five years later, and the cement is fine, but the bricks are not. They are turning into brick dust and with every rain, more and more is washed away until the damp penetrates inside and ruins the nice new wallpaper. Why? I hear you students of architecture ask. Well, brick walls are supposed to absorb rain and act a bit like an overcoat – the top surface gets wet, then dries out once it stops raining. Most of the drying out takes place through the joints, which in old walls, are made of lime mortar which is softer than the bricks. Over time – and we’re talking about many years, sometimes hundreds, the joints erode, but that is relatively simple to repair – you just bung in some more lime mortar.
If you use mortar which is harder and more impermeable than the bricks, such as cement – guess what? The wall will dry out through each brick and not the joints. That means the joints stay pristine and as good looking as the day they were done by the wretched man with the tattoos and the Transit, and your precious little bricks, the wonderful little darlings that are holding your house up, start eroding. Just look at the photograph. The bricks are over 140 years old. The remains of the modern cement mortar are no more than about 30 years old.
Be warned!
It makes me want to weep when I see poorly laid or badly repaired brickwork. It’s only too common, unfortunately.
Picture the scene: a woman opens the door to a rough looking man who has just stepped out of his unmarked white Transit – ‘Your house needs pointing, luv – you don't want damp walls! I’ll do it for you – with the real thing, cement and none of that dirty old lime mortar’. She agrees, of course, who wants damp all over their nice new stencilling? After discussing it with her husband, who becomes worried about his perfectly good, if old, brickwork, they agree to pay the exorbitant cost.
Two weeks later, the damage is done, and the brickwork is now traced with the sharp, hard, ruled lines of blueish cement mortar, with added splash marks and a stain on the patio where the cowboys have mixed the wretched stuff without putting some protective boards down. Cement mortar is very hard, sets quickly and is made from Portland cement. You can buy it in little bags from B&Q and it is a grey blue powder. Mix it with water and sand and Bob’s your uncle – a wet, sloppy substance which the cowboy builders swear by (among other nasty things).
Five years later, and the cement is fine, but the bricks are not. They are turning into brick dust and with every rain, more and more is washed away until the damp penetrates inside and ruins the nice new wallpaper. Why? I hear you students of architecture ask. Well, brick walls are supposed to absorb rain and act a bit like an overcoat – the top surface gets wet, then dries out once it stops raining. Most of the drying out takes place through the joints, which in old walls, are made of lime mortar which is softer than the bricks. Over time – and we’re talking about many years, sometimes hundreds, the joints erode, but that is relatively simple to repair – you just bung in some more lime mortar.
If you use mortar which is harder and more impermeable than the bricks, such as cement – guess what? The wall will dry out through each brick and not the joints. That means the joints stay pristine and as good looking as the day they were done by the wretched man with the tattoos and the Transit, and your precious little bricks, the wonderful little darlings that are holding your house up, start eroding. Just look at the photograph. The bricks are over 140 years old. The remains of the modern cement mortar are no more than about 30 years old.
Be warned!
11 comments:
Bricks are indeed wonderful things. I'd heard that bricks absorbed water, but I'd never realised that the lime mortar was so important in such a subtle way.
It reminds me of one of Stewart Brands books in which he mentions brick and says that one wonderful thing about it is that it looks bad (like your photo) before it acts bad (ie collapses). That truely is a great feature!
Thanks, Alice. I never knew that about the different mortars. Makes total sense. I love learning stuff like this!
Oh I get it, you end up with a filigree house. Does the same apply to traditional wall plaster, that it was designed to 'breath'?
I am think your bricks are fascinating, but then I have a collection of photographs of dry stone walls!
Thats my "something new everyday" for today.
Can't wait to get back to work and drop that little nugget into conversation. Oh yes, we have very erudite conversations, design and technology form a large part of our day, after all the girls boobs and Arsenals latest signing have been exhausted!
And you just thought I was shallow!
Pete - you are right - I have never ceased to be amazed at just what will stand up, despite very little visible means of support. I don't know if you've heard the engineer's comment about a timber framed house: 'the only reason it is still standing up is because the woodworm are holding hands in the holes'
Deb - those are only two of myriad mortars... aah! I could go on forever...
Uphilldowndale - yes, buildings need to breathe, just like we do. Think of cement mortar and plaster as the equivalent of putting a polythene bag over your head.
TUPC - I am relieved to hear building technology forms the greater part of your conversation at the local tea hole or in the canteen. You may like to drop in a few hints about penny struck and tuck pointing, and their relative merits, as well. Especially good for charming the ladies.
Gosh Alice. After reading what you said to tupc, I've been wondering about what on earth your courting conversations were like.
Could make a good question for my blog!!!
Go for it dickiebo. Let's hear yours first!
Dickiebo, I would like to be a fly on the wall when TUPC tries the chat up line: 'come and see my tuck pointing'!
That's a nice one - best left to the imagination, methinks.
Oh dear - I crashed and burned when I tried it Alice - But now I've had another look, I think I might have got my words mixed up!
*Sigh*, I saw some really nice bricks at the weekend
http://uphilldowndale.wordpress.com/2008/02/12/how-does-your-garden-grow
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