Brick Wall Reinforcing

Haydin

I figured I'd go straight to the people in the know here. I am in the process of designing a roof terrace in Utah that will sit up on the papapet walls of an old building. The building has 12" thick brick exterior / block interior walls 19' tall from the early 1900's. The existing walls are sound and have had structures on top in the past that were removed due to fire. I have a 50' opening between two adjacent buildings that will be bricked in with standard brick. Anchoring to the end walls is no problem. What is a concern is reinforcing the wall mid span. The wall is going to be 8' tall and sitt on the existing parapet. Of the 12" existing parapet, I'll need 4" for the terrace bearing. That leaves 8" for the brick wall thickness. If you were going to build something like this, what sort of bond bracing / brick interlock technique would you use? Thanks, Haydin

thom

If it was me, I'd hire an engineer.

Look, you're way beyond your pay grade here. You're adding weight so you may need to check the foundations and the lintels on openings below. You need to insure proper horizontal and vertical load capacity. You've got to deal with wind loads and possibly seismic loads. Then there's the supporting structure for the deck that must be dealt with.

You can't get engineering over the internet. It would be worth the paper it's (not) printed on.

concretemasonry

It sounds like you want to set an 8" thick, 8' high wall on the existing 12" wall. if this is correct, you have two things to be concerned with:

1. The method of attaching the new 8" wall to the existing wall below. This parapet would be classified as a cantilever wall because there is no support at the top.

2. The new 8" wide, 8' wall wall will need vertical reinforcement, which could require a slightly thicker wall to provide a grout cavity between the two wythes of brick. This could involve setting the wall on the terrace slab and a special detail. Bonding and "interlocking" are not effective in increasing the strength of a parapet wall.

This could be a very high liability job and needs an engineer.

Having walls that only take vertical loads and a little wind is one thing, but a parapet/cantilever wall is a totally different animal and has different types of loads.

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Dick

Engineer, designer and consultant recently active domestically and internationally on construction and design in about 35 countries.

Haydin

thom, Thanks for the reply! This building used to have 3 additional floors on it at one point in time. The building burned and all was removed down to the main street level unit that maintains 19' of the original 50' +/- height. For sake of argument, figure a 100 times more weight than the wood floor terrace that will be going on it now. What I was looking for is a method for building a 50' long x 8' tall x 8" thick brick wall. It will be attached at both ends. It's the mid section that I was looking into options for. I was seeing if there were any innovative or traditional methods of interlocking or bond reinforcing the brick that would allow the wall to run a straight shot without any exterior bracing. The wall would be it's own reinforced entity. I have found that the trades out there are in many cases more informed than engineers that have never stepped a foot in the field! P.S. I have local engineers that in the end will review and seal. I just want to look at the options first.

Brickie

You will still need exterior bracing, way too many variables, better safe than big time sorry. As Thom & CM stated, there's big time liability involved and you definitely need the services of a knowledgeable engineer

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Tscarborough

The engineer stamp is not to provide the best solution, it is assign the liability.

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It ain't Rocket Science unless you are building rockets.

concretemasonry

TS is right about the assigning liability and removing a great deal of it from your shoulders.

A good engineer will be able to give you some options if you are paying him. If the owner or GC pays you may get no choices, but you will have to build it as designed.

__________________
Dick

Engineer, designer and consultant recently active domestically and internationally on construction and design in about 35 countries.