Tips for constructing a ledger board deck

Attachment to brick requires unique engineering

By Inman News Feed
Add Comment Add Comment | Comments: 0 | Posted Jan. 20, 2012

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Attachment to brick requires unique engineering

Paul Bianchina
Inman News®

Q: My son is planning to add a deck to his 1928 row home soon. He will be doing most of the work along with my other son, who built his own deck a few years ago. The question is how to attach the ledger board to the vintage double-brick construction. A contractor friend told him to use "blue" screws to attach the board to the building and then drill all the way through into the basement and use lag bolts to attach. Is there a better way or does this sound like the best method? --Linda Q.

A: In my experience, I've seen only two effective methods used for attaching a ledger in this type of construction, and both were designed by structural engineers.

The first was done by drilling holes all the way through the bricks. Large-diameter bolts were passed through wide washers, called bridge washers, then through the ledger and through the bricks, into the inside of the building (in that case it was into a basement).

Steel plates were placed over the bolts on the inside of the building, to distribute the load over a larger area of the brick, then the bolts and the ledger were secured with lock nuts.

The second method was done where through-drilling wasn't possible. In that case, larger holes were core-drilled into the first layer of brick. The holes were filled with an epoxy mixture, and anchor bolts were embedded in the epoxy. The ledger was then attached to the anchor bolts with washers and lock nuts.

Attaching structural framing to solid brick construction, especially with bricks that are as old as the ones in your son's home, can be very tricky, and even dangerous if not done correctly. Lag bolting is typically not an approved connection method.

As I mentioned, the two examples I gave were designed by a structural engineer, and were designed for the specific size of the deck, the construction methods being used, the condition of the bricks, and the amount of load being imposed on the structure.

Because your son will have to get a building permit for the deck, the building department should also be able to help him with some of the attachment details, or can recommend a qualified engineer to assist with the design.

An incorrectly designed and constructed deck is an accident waiting to happen, so please don't take any chances!

Q: My 1975 split-level home is brick-faced with aluminum siding all around. I wish to place exterior insulation, hard-panel type on the exterior foundation wall (of the basement). The exterior foundation was backfilled in after the house was built. The interior walls of the basement have not yet been insulated, but I will do that in the future.

Questions:

1. I will dig around the foundation wall to place the insulation at 3 feet below the frost line; that would make the panel length required about 7 feet, with 4 feet being visible. What kind of insulation is best for this location?

2. I would paint the insulation panels to match the concrete, using exterior latex. Is latex the best paint system to use?

3. Do you think this would reduce the heat loss from the basement walls to the exterior, and is it cost-effective?

4. Do you have any articles regarding the insulation of the exterior walls? --John P.

A: You might want to consider just placing the insulation on the interior walls. As long as your basement is dry, this would save you some expense, as well as a lot of additional work. It also reduces the risk of termites, which can become a problem in some areas where foam board is used below grade.

To answer your specific questions:

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