Part of our 1930's house is made in heavy red engineering brick which
is itself very strong.
The motar is even stronger - It is not easy to remove a section of
brickwork without damaging the bricks. Neighbours have reported the
My 1:3 morter is nothing like as tough. I was wondering - how did they
make such strong mortar?
Probably by using sharp sand instead of building sand. That turns a mortar
mix into something akin to concrete which will set rock hard and stick to
bricks like that stuff to a blanket. It's far too inflexible for bricklaying
though. It may well have been a mistake by the original builders.
Could it have been repointed? Just had a guy at the door asking if I wanted my
chimneys repointing as they were doing the house next door. We had noticed
- everything is covered in dust from the machine they use to rout out the old
Oh? Wish you had told nme that before I built a whole garden wall with it..
Didn't seem hard to me. I always like to use sharp sand.
1:2 mortar is about as hard as it gets tho. After that the cement has
preetty much filled all the gaps between the sand..
I did add some PVA glue (about 250ml in a standard bucket) when I was
doing some plastering, and that made it a lot more difficult to sand down
after it had set.
Would it have any effect with mortar and would there be any good or bad
I've done this to make up a small ammount of bonding coat when I
only had finish coat, but it's not a normal thing to do.
I certainly wouldn't put it in the real finish coat.
It is used in mortar sometimes, but 250ml sounds like way too much.
1-2 teaspoon fulls per shovel of sand would be about right.
It improves the tensile strength, but even so, you should build
such that you are expecting any tensile strength.
If this is for outdoor use, use Exterior PVA (which is EVA), which
also makes the mortar more waterproof. (PVA isn't waterproof.)
[email address is not usable -- followup in the newsgroup]
I'd heard that adding PVA to the mix help adhesion and as it was my
first attempt at plastering thought I'd give it a try.
As I was stiring it in I tropped the cup full in the mixing bucket.
It mae it a bot more difficult tom smooth off as the plaster stuck more
to teh trowl and as I said it made sanding down to a flush finish so much
So I eneded up thinking that if I needed a really strong and difficult to
in the future all I need to do is add PVA.
I was using one coat plaster at the time.
It also made the coat whiter.
cheers for that info it'll be useful when I patch up the front step :)
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