rowdy48

I looked at a 5 year old home that had vinyl windows and could see where the bottom of the window was bowed or bucked from the crush of the brick. How many rows of brick can be layed before you have to let them set and dry. It seems builders ( or masons ) brick to many rows. I have seen othe homes where the window sill is push down on the ends as if they are bearing weight. Is this also from placing and bricking the lintel too soon?

Thanks

inspectorD

Rule of thumb is 4 feet. Also depends on how soupy the mortar was mixed, and what they used.

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oldognewtrick

Inspector, I'm curious as to where this rule of thumb comes from, cause as a roofer I see MANY problems with mortar with a high sand content wicking water into a structure, homeowners having a "roofing" leak and no mater how many times the other roofer reshingles or reflashes the brick it still leaks. Is there a "standard" for mortar/sand ratio, who checks this cause the codes dept told me they will not take on the liability of inspecting brick cause "none of its done right".

You wouldn't believe how many chimneys and wall we have sealed to stop leaks in brick. It seems like this is becoming a bigger problem all the time.

inspectorD

It comes from the ol Italians masons, the weight of the brick needs to be adressed before the mortar partialy sets up.
And the mix depends on what brick you are using and how it was made.
Look up mortar mix, and see what you get, there is plenty of info on the masonary sites.
As for leaks, that is a whole nuther set of issues. Brick absorbes water, it is not to be used without a weather membrane like 15# felt(tar)paper behind it, each seam lapped over the next.
And last but not least, there are many non professionals who do masonary work, and make the scenario a big problem.
I'm sure there are great folks who do great work out there, but they are getting scarce.
Hopefully someone with more time will explain further, and more accuratly.

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stuart45

The strength of the mortar depends on the type of bricks used. The general rule is that it should be weaker than the bricks, so that any movement in the wall will crack the joints and not the brickwork. Nowadays 3/1 sand/OPC is used below DPC level, and above with ordinary clay bricks 5/1 or 6/1 with added plastizer. 6/1/1 sand/lime/OPC is also used.
The height of brickwork in a day depends on the type of bricks used. With a dense engineering brick only 4 courses a day may be possible. On site 20 courses or 5 ft is usually allowed with facing bricks, although if the bricks are wet this can be a problem. Even with dry bricks there is some settlement, and when you put a level up the centre of the wall the next day you can often see that the wall has moved out slightly.
On chimneys nowadays we put in a lead tray through the brick courses just above the lead flashings to help prevent damp penetration.

mudmixer

The weakest mortar that can carry the load is what is recommended. Excess cement creates more problems and it far better to use other materials (lime, etc.) that enhance the other mortar properties like workability (the prime item), bond, low permeability and flexibility. Brick does not control the strength of the mortar according to the British Masonry Society or U.S, groups and standards. It is just a material that has to work with other materials.

A wet brick or even a dry brick with a poor rate of absorption will influence the height that can be laid. Proper workability is absolutely necessary. there is a big difference between architectural clay brick and concrete brick (which are still common in the muti=wythe/leaf walls that are still used in the U.K.

The form of the brick is also a big factor. A plain, wet brick will "float" and there is no way it can be laid quickly. Cored or "frogged"brick are less likely to float because they provide a mechanical "lock" between the brick and mortar. If the brick are wet or have a very low rate of absorption, they cam only be laid slowly. Additional cement requires more water, which makes things worse.

Dick