How To Build a Modified Post and Beam Frame

If you want the look and strength of timber framing without the hassle and cost, try a modified post and beam.Heavy members that one can't hoist alone are used in both timber framing and post and beam.A modified post and beam can be built almost entirely out of cheap boards.The boards wrap a skeleton of posts.

Step 1: A sturdy foundation is what you should build upon.

Even better is a pole foundation, where your posts are embedded deep in the ground, and transfer the full weight of the building directly underground.This has great stability.

Step 2: Put your posts in a grid.

4x4's are too flimsy to be used in the sun.Remove the rotten horizontal members and keep the treated posts if there is an old structure you can build on.Remove and replace boards at a time so they don't fall down.

Step 3: Get your posts plumb.

Once they're plumb, brace them.If you're dealing with old posts that have fallen out, you should use rope.Attach the rope to the post with a nail and pull until it's plumb.If you have to, tie the rope off on nearby posts and trees.

Step 4: You should choose the right boards for your beams.

The size of the boards depends on how far apart the posts are.For posts 10' apart, 2x12 is typical.2x12 is unnecessary if you have a stem wall and perimeter foundation, and you can put in additional studs to support the beam.2x10 will be more than enough.

Step 5: Decide the beam height.

To mark each post, use a laser.Set the laser level on a raised level platform and shoot and mark the red dot on each post as you turn your aim from post to post.Measure up the same distance on each post that you have decided should be your beam height.To get a perfectly level line, use a torpedo level.The horizontal boards for the beams are supported by your vertical cleats.

Step 6: Attach your cleats to the posts.

The cleats should be 2' to 3' in length.The cleats will help carry the weight of the beams and give you a place to put the large-dimensioned horizontal boards.If you have a stem wall, cleats should be run all the way down to the block to further strengthen the posts.borate is fine if the cleat is touching the block.Attach a piece of flashing to the bottom of the board if it isn't possible.A small piece of foam insulation could be used.

Step 7: The first horizontal board should be raised.

The board should go 'crown-side' up so that the weight doesn't cause it to fall.The longer the lumber, the more likely it is to have a crook.The arch goes up.

Step 8: If the beam placement is high, use rope to raise the board.

Attach rope to the end of the board and tie it to a post on a ladder.Go over to the board end on the ground, walk up a ladder, attach rope to it, and tie it up.When you get the board up on your cleats, go back and forth raising it.Use a rubber mallet to move the board into the correct position, and hold it there with either bungee cords or clamps.

Step 9: Fasten the board.

If possible, try a combination of long screws and big nails.Attach the board end to the post first so that it won't move.When a board is clamped, hammering in large nails will cause it to move.One way to hold it in place is to put a screw in it.The board should be all the way down and fast to the post after the nail is in.Come back with screws.The board will split if you stay away from the edges of the board.You want enough bolts to hold the board in place, but not so much that it will stress the wood.5 staggered fasteners is fine for a 2x10 with an overlap of 2 to 3 inches.

Step 10: There are cleats and a horizontal board on the other side of the posts.

The beams will be composed by two horizontal boards on either side of the posts.To find out where your cleats should be on the other side of the post, use a torpedo level to mark a level line from your original line to the back.Attach boards with a variety of nails and screws first so the boards are flush.If screws are too expensive, try ring-shank nails...They must be driven carefully or they will bend.

Step 11: If you have a perimeter stem wall, put in studs to support the beam.

Doubled 2x6's are very strong and can be sistered with inexpensive spiral nails.To mark where the studs will go, you have to measure the sill plate.If your posts are 10' to 12' apart, divide the space into thirds.You will have plenty of room for windows.It's better to use metal angles to anchor the studs than toe nail them.Get the studs plumb.Bar clamps are the easiest to work with.

Step 12: The boards in the beams should be interlocked with the top of the studs.

The weight is taken by the wood and not just the bolts.To finish the cuts, use a jigsaw.

Step 13: If possible, frame around the corner with cleats, parallel boards for beams, and doubled studs.

If a horizontal board can't be attached to a post, use a joist hanger.

Step 14: Follow the pattern throughout the perimeter.

If you want stability, tie 4 posts together in a square.The center posts of the structure have parallel beams running through them.Joists will be hung from the beams.Every 24 hours, blocking composed of double scraps of 2x6 is placed.To stiffen them, within the beams.This blocking will be tied directly into by Joists.

Step 15: In the opposite direction of your beams, run 2x6 bracing.

Joists simply sit and take weight from above.Run the braces just under the beams so they can double as cleats for the center beam boards, as well as provide additional spots for metal connections such as metal angles.

Step 16: Make sure the center posts look like this, with 2x6 bracing run underneath the beams, all of it tied together with metal angles.

The bracing and beams are going to be blocking.

Step 17: The 2x6 bracing needs to be tied into the perimeter framing.

Step 18: Continue to work by the square.There is a possibility that this is not the case..

Step 19: The weight can be supported by placing an X-frame over the garage doors.

The bottom and diagonal bracings are made of 2x8's.

Step 20: Until the majority of the structure is stable, follow the same techniques of cleats, beams, and blocking.

Diagonal braces andgirts can be used to strengthen the walls if additional studs are not compatible with your design.

Step 21: Once the frame is finished, put the joists in.

2x10 has a spacing of 24o.c.It will easily take the weight of an upper story.The frame will be similar to this.