Beams on 4x4 post


Old 06-18-09, 09:30 AM
Thread Starter
Join Date: Jan 2007
Location: Danvillle
Posts: 21
Received 0 Votes on 0 Posts
Beams on 4x4 post

Hi all, Getting ready to build a 16'x18' wood deck, 24" off the ground to the top of the floor. Using 2"x10"x16' beams, 2"x8"x8' and 2"x8"x10' joists and 5/4 decking.

I have used Virtual Deck Designer to get my basic design and materials list. One of the things they show is putting the 2x10 beams either side of the 4x4 post. I have built a few decks in the past and I have always put the the 2-2x10 togeather (screwed togeather) and set them on top of the post. Any opinion which would be better? Doing it the VDD way would be easier to handle one 2x10 at a time but putting them on top of the posts seams that it would make for a stouter support??

Under the deck I am going to dig up the sod and transpant to some bare areas in the yard. Then I was going to put down plastic over the dirt...any opinions here?

Thanks for opinions...Mark
Sponsored Links
Old 06-18-09, 10:58 AM
Kevin Stevens's Avatar
Join Date: Jun 2009
Location: Wild wild west, Colorado
Posts: 34
Received 0 Votes on 0 Posts
side by side is stronger

mounting the "beams" together as a single beam is stronger but not by too much. In filling the space between the beams with a piece of 4x4 will give you the same type of resistance to twist that the paired beam have. but is still overkill.

The catch to mounting the beams to the sides of the post is that you need to bolt them...screws will not be strong enough. A pair of 1/2" hex bolts will do fine, in areas with very high snow loads we often use 5/8" bolts. the nice this about side mounting is you can use hand clamps to postion the beams for level on taller posts..once the bolts are installed (i use a 5/8" paddle bit for 1/2" bolts) you trim off the top of the post flush with the beam top or even tie it into a joist if you spacing allows. I like the clamp method because I often work alone and its like having someone else holding up the other end.

more important than beams sometimes is how the footers are placed...Frost depth 8" piers are still my 1st choice, embedded j bolt and AB44 post bases.

Removing the sod, is a great idea, it will die otherwise. plastic is good but landscape fabric is also another option...for visual effects you could even lay some crushed stone or bark...
Old 06-18-09, 11:23 AM
Thread Starter
Join Date: Jan 2007
Location: Danvillle
Posts: 21
Received 0 Votes on 0 Posts

Thanks Kevin...I've got clamps...didn't even think of using them! Also filling in with 4x4 to prevent twist...good idea. I tend to over build anyway. Going to put bridging between the joists. I had planned on using AB44 post bases. Not sure I like the landscape fabric option. Most of what I've read says it needs to replaced approximately every 5 years and the deck will be close enough to the ground that I would not be able to replace.
Old 06-18-09, 11:42 AM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 21,119
Received 2 Votes on 2 Posts
Under the deck the fabric would probably last much longer. No exposure to light or any real weather.

The fabric will also allow water to drain through, whereas plastic wouldn't. Water could pool up and be a mousquito farm.

I'd use the fabric with stone placed to keep it where it belongs
Old 06-18-09, 03:45 PM
Join Date: Mar 2009
Location: WA
Posts: 1,167
Received 0 Votes on 0 Posts
Here is a good read on frost heave, piers with footings, gravel under, plastic around pier, ect.

Building a deck: expert advice from ... - Google Books

Be safe, G

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Ask a Question
Question Title: