Setting Beam Height for Your Deck

Setting beam height - an important step.

Once you have determined the height of the first level of your deck and installed the ledger board it is time to think about setting the height of the supporting beams. This will allow for proper water flow away from the house and ledger connection and yet still look good to the eye.

Rule of Thumb

Allow for about 1 inch of slope for every 5 feet of deck projection. So over 10 feet, slope your deck about 1.5 to 2 inches.

Use a Laser or Line Level

4x4 post bracket

Place a 4x4 into the anchor bracket on the concrete pier and lightly tack it in place at vertical to the ground.

Use a line level or a laser and shoot from the top edge of the ledger board to the 4x4. Mark this spot. It represents perfect level.

Find out how far your beam is from the house and use the rule of thumb above to calculate how far down the deck should be at that point away from the house.

In our case the beams were 6 feet away from the house. So the deck surface should be about 1.25 inches below level at that point.

Decide on Your Beam Detail

Beam arrangement for a deck

In our example we used 2 laminate 2x8s (7.25 inches high) and set the beam directly on top of the 4x4 post. We also used some metal strapping and brackets to securely connect the beam with the post.

Starting at the line for perfectly level, measure down the thickness of the deck boards, joists, and the beam itself. Mark this point on the post.

This is where you will cut your 4x4 posts and since they are only tacked in place, they can easily be removed for cutting. Think about setting beams so they extend beyond the perimeter of the deck wherever possible. They can be cut to exact size later.

Alternate beam arrangement

Notice how we created a 90-degree corner beam on this deck to accommodate the "bump out" where the joist direction changed.

OK, you have made some great progress! Setting beam height is an important step in the deck building process. It is now time to start framing.

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