It is currently 29 Mar 2024, 06:58
Mike G wrote:NO! Mortar and concrete are 6 to 1 other than in exceptional circumstances. A concrete fillet tapering to zero is an exception, and 4 or 5 to 1 there would be better.....in that particular circumstance. I come across this a lot. I have no idea why people are being led into over-strong mortars in particular, which are a really bad, harmful idea. Over-strong concrete is a waste of money, but doesn't actually have a great downside structurally.
Woodbloke wrote:Our house was built in 1947 and for some strange reason, the entire South facing wall was constructed with what seemed to be almost pure sand as a mortar mix. I had to have it entirely re-pointed a few years ago which took a pair of brickies two days; at the rate I could do it, it would have taken me two years - Rob
Mike G wrote:I think the theory is that the rock hard pointing forms an impervious shelf every 3 inches up the wall, which water then sits on. That keeps the bottom edge of each brick damp. Wet bricks (and particularly differentially wet bricks) + a frost = possible spalling. Lime mortar allows the bricks to dry out more completely, and so the risk is much reduced.
There are complications with that, too, including the fact that old bricks were fired in wood-fired kilns, and so could vary enormously in their hardness (depending on where they were stacked). This makes older bricks more susceptible to frost than modern ones.....so any little thing which disturbs the equilibrium of an old wall is best avoided. If they were laid in lime originally, they should be pointed in lime now.
Mike G wrote:I think the theory is that the rock hard pointing forms an impervious shelf every 3 inches up the wall, which water then sits on. That keeps the bottom edge of each brick damp. Wet bricks (and particularly differentially wet bricks) + a frost = possible spalling. Lime mortar allows the bricks to dry out more completely, and so the risk is much reduced.
There are complications with that, too, including the fact that old bricks were fired in wood-fired kilns, and so could vary enormously in their hardness (depending on where they were stacked). This makes older bricks more susceptible to frost than modern ones.....so any little thing which disturbs the equilibrium of an old wall is best avoided. If they were laid in lime originally, they should be pointed in lime now.
Mike G wrote:I think the theory is that the rock hard pointing forms an impervious shelf every 3 inches up the wall, which water then sits on. That keeps the bottom edge of each brick damp. Wet bricks (and particularly differentially wet bricks) + a frost = possible spalling. Lime mortar allows the bricks to dry out more completely, and so the risk is much reduced.
There are complications with that, too, including the fact that old bricks were fired in wood-fired kilns, and so could vary enormously in their hardness (depending on where they were stacked). This makes older bricks more susceptible to frost than modern ones.....so any little thing which disturbs the equilibrium of an old wall is best avoided. If they were laid in lime originally, they should be pointed in lime now.
Regex wrote:Woodbloke wrote:Our house was built in 1947 and for some strange reason, the entire South facing wall was constructed with what seemed to be almost pure sand as a mortar mix. I had to have it entirely re-pointed a few years ago which took a pair of brickies two days; at the rate I could do it, it would have taken me two years - Rob
Sounds expensive!
spb wrote:The main problem you'll have with 25x38 is where two cladding boards meet, and you'll need to nail both of them into a single counterbatten. 38mm doesn't give you much leeway in being far enough away from the end of the cladding but still hitting the batten.
Mike G wrote:I really would hesitate before buying a flip table-saw/ chop saw thingy. The ones I have seen (I've not seen this one) were very compromised, and second best at each job. I would buy a tool that's going to be useful in the long run, and maybe that's more likely a chop saw, or just use a couple of horses and a hand saw. It's very much quicker and easier than you'd think. The first house I built was a pseudo barn conversion, entirely boarded, and I did that by hand.
9fingers wrote:I think Lidl's Parkside Track Saw is coming up again on 6th June which might be of interest. Always heavy demand for these so you could quite likely sell on after the job if you did not want to keep it.
Bob
Mike G wrote:I really would hesitate before buying a flip table-saw/ chop saw thingy. The ones I have seen (I've not seen this one) were very compromised, and second best at each job. I would buy a tool that's going to be useful in the long run, and maybe that's more likely a chop saw, or just use a couple of horses and a hand saw. It's very much quicker and easier than you'd think. The first house I built was a pseudo barn conversion, entirely boarded, and I did that by hand.
Mike G wrote:I'm pretty sure that I've never put the DPC down directly on the brick. A slurry of mortar smooths out any irregularities, and ensures the DPC is undamaged by the pressure of the building on it.
Mike G wrote:I think the theory is that the rock hard pointing forms an impervious shelf every 3 inches up the wall, which water then sits on. That keeps the bottom edge of each brick damp. Wet bricks (and particularly differentially wet bricks) + a frost = possible spalling. Lime mortar allows the bricks to dry out more completely, and so the risk is much reduced.
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