I have an old house and am repointing some bricks. I would like to know what the mixture ratio is for cement and sand. I have heard anywhere from half and half to 3 times sand. I have to have an almost white color so I can't use the premixed motar. What I have been mixing ( half and half) seems to fall away when it dries. Thanks for any help.
Use white cement if needed. (5) sand - (1) cement - (1) hydrated lime.
If it crumbles when it dries, either your cement is too old, or you didn't use enough water. Also, you should wet down the existing mortar and bricks before applying the new mortar. Otherwise, the existing masonry will suck water out of your new mortar and weaken it.
G Henslee's recommended mix is good advice. You really need some lime in there to increase the workability of the mix; it makes the mortar stickier, too.
-- Regards, Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?
How old is that home? Using modern mortar on old brick can cause damage. You may need a special mix to prevent damage.
Hmmm.... never heard that before. Can you be more specific?
-- Regards, Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?
It's important that the mortar not be as hard as the bricks. Old bricks were not as hard as todays bricks, but the old mortar had much more lime than todays mortar. If you try to use a new -0high cement mix mortar with the old softer bricks, the faces of the bricks will start to spall off.
John
Thanks, John - do you have any idea why that is?
-- Regards, Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?
Not a friggin clue, but to make a wild assed guess, I'd say that materials all move, even something as rigid seeming as a brick wall, and when things move there's got to be some give: you engineer that give into the mortar while it's the bricks that give the strength to the wall. If the mortar is stronger than the bricks, then you're trying to make a concrete wall with very large aggregate.
John
Meehan"
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