Econo-Deck: Building A Basic Deck Part 1 - Framing

By Bruce W. Maki, Editor

Building A Solid Deck Foundation:

The first step in our deck construction was to determine the location. We centered the 6' x 6' deck relative to the front door of the house.

The local building department told us that no permits were needed because the deck was not attached to the house and was less than 30 inches above ground. (This may not be the case in your community... call your building department.)

 

We dug holes in the soil for the 4x4 treated deck posts. The soil here is so sandy that the building department did not specify a footing depth. We dug the hole until we struck the footing of the concrete foundation, about 30 inches below grade. After packing down the soil with a board, we placed an 8"x8" concrete paving stone in the hole to spread out the weight of the post.

Normally, all footings are required to be deeper than the expected maximum frost depth. Here in Northern Michigan, frost can be expected to penetrate up to 48" deep. However, much of this region has soil that is completely sand, soil so well drained that there is almost no risk that ice will form below the footings and heave the structure. Indeed, the garage on this property, built in July 1999, needed only a slab-on-grade foundation.

 

We dug a second hole about 6 feet away, and also installed a concrete paver. We placed posts in each hole and made a mark on them that was the same level as the bottom of the vinyl siding. We had easy no way of being sure that both holes were the exact same depth.

 

We built an "H" shaped section with two 4x4 posts and a 72" 2x6. The horizontal board will be a beam that supports the joists. The "H" section was placed in the holes and checked for plumb and level. The holes were filled in part way.

The height of this horizontal 2x6 was determined by the final height of the deck surface. We wanted the deck about 7" below the door sill. (A normal step height.) The decking is 1" thick and the 2x6 joists are 5.5" deep. These numbers gave us a dimension to locate the beam relative to the bottom of the siding.

 

A second 2x6 was added, sandwiching the posts. A third hole was dug and a post put in place. We attached a joist to hold the third post at the desired distance from the first pair.

Important Step: Getting the correct position of the posts is crucial to making the deck turn out right. With the joist attached but the hole not yet filled in, we measured off a 3-4-5 triangle to make sure the third post was exactly perpendicular to the first pair of posts. Then we filled in the hole.

 

We dug the fourth hole.   With the fourth post in the hole we clamped a joist in place and made it level. We also dug a hole for a fifth post that will hold the hand rail in place.

 

After making sure the joist was level, we secured it with 3" deck screws.   We attached the fifth post to the joist.

 

We partially filled in the last two holes...   ...while making sure that the fourth and fifth posts were plumb and square with the first three posts.

Positioning the last posts: With the post holes halfway filled with loose soil we were able to adjust the posts side-to-side to make the final "leg" perfectly parallel with the other side. (The side we made square with the 3-4-5 triangle.)

 

Then we attached the rim joist and part of the 2x6 beam that will support the joists. Another view.

 

The second 2x6 was added beneath the joists to complete the beam.   We laid out the joist locations on the beam.

 

We positioned the joists, spaced 16" on center. At the outer end we drove 3" deck screws through the rim joist into the ends of the regular joists.

 

Near the house, we drilled pilot holes so the deck screws would go where intended. A long bit extension helps when driving screws in tight places.

 

The screws were placed a little off center, to prevent colliding with screws driven into the other side.  At each joist we drove two screws into the beam, one on each side of the joist.

This completes the framing of the deck.

Follow the story as we install the deck boards.

Copyright © 1999, 2005  HammerZone.com

Written August 22, 1999
Revised January 5, 2005