Home & Garden

Enlarge deck with untreated wood beam

  • Last Updated:
  • Aug 12th, 2019 6:44 pm
Tags:
[OP]
Newbie
Dec 8, 2010
80 posts
20 upvotes
Granby

Enlarge deck with untreated wood beam

My current deck is 8'x5' supported by the beams (untreated) extended from the house. For the last 35 years, these beams are covered and protected by the outdoor plywood floor (see pictures). I plan to enlarge the deck to 12'x12' using composite boards. The new beams will be treated wood attached to these existing untreated wood beams. Since water will get to these untreated beams, please suggest a way to protect them from getting rotten? stain with wood preservative? Or cover the top down to a few inches with aluminium sheet or some kind of construction tape?

For the footings, I plan to use industrial heli piles which cost ~$200+tx each installed. In my case, 4 heli piles (2 at 2' and 2 at 10' from the house foundation). The only part that is attached to the house is the new beam attached to the existing beam. Do you see any issue with this structure? Do you have any comments on heli piles for deck footings?

Really appreciate you help.
Images
  • IMG_20190805_195031310.jpg
  • IMG_20190805_195143627.jpg
32 replies
Deal Addict
User avatar
Aug 12, 2007
3795 posts
547 upvotes
Waterloo
nano69an wrote:
Aug 6th, 2019 11:52 pm
My current deck is 8'x5' supported by the beams (untreated) extended from the house. For the last 35 years, these beams are covered and protected by the outdoor plywood floor (see pictures). I plan to enlarge the deck to 12'x12' using composite boards. The new beams will be treated wood attached to these existing untreated wood beams. Since water will get to these untreated beams, please suggest a way to protect them from getting rotten? stain with wood preservative? Or cover the top down to a few inches with aluminium sheet or some kind of construction tape?

For the footings, I plan to use industrial heli piles which cost ~$200+tx each installed. In my case, 4 heli piles (2 at 2' and 2 at 10' from the house foundation). The only part that is attached to the house is the new beam attached to the existing beam. Do you see any issue with this structure? Do you have any comments on heli piles for deck footings?

Really appreciate you help.
If This was in my city ( Waterloo) , If I touched it with a toothpick , I'd have to tear the entire thing down and do it over entirely since this isn't code anymore.cant have an over hang more than 24".

Check your bylaws and get a permit before you touch this.

I would cut this off and make an entirely new deck.
----
Pay it forward.
Deal Guru
User avatar
Nov 18, 2005
10893 posts
2220 upvotes
Kingston
I hate to go "Mike Holmes" on this but definitely tear it down and full replace. What is supporting the deck now other than the attachment to the building?

If this was in my city it would require a building permit to add to or replace. Which is a good thing as they would stop you from making mistakes (like building an addition to this deck).
Member
Jan 19, 2017
475 posts
439 upvotes
Number of things. New deck will require a permit, the seating/rail is not to code, the overhang is not to code and most importantly to me, the thermal bridging within joists extended outside makes this method of construction a very very bad idea. As others have noted above, Id recommend cutting those joists down (if they arent already rotten) and install a new ledger, and start from scratch. Retrofitting into it will not meet code, and even if it did, you arent saving much money at all by salvaging it.
Deal Fanatic
May 29, 2006
9671 posts
2334 upvotes
dude why would you even remotely consider using any part of that old deck, rip it out and start new.
Sr. Member
Dec 18, 2017
526 posts
221 upvotes
London, On
How does that not fall down now? Are those floor joists the actual floor joists of the house just extended out beyond the foundation? If so, I don't know how you deal with that. But since you are getting footings installed, just build entirely new off of those and don't even attach to the house. Your footings are essentially an 8 foot square so you can decide which way to put the support beams based on which way you want your decking to run in relation to the house. Check your local code about what size lumber can overhang 24 inches. (your beams will overhang the piles 24 inches on either end, and the floor joists will overhang the beams 24 inches either side).
Deal Fanatic
Jan 25, 2007
7030 posts
3210 upvotes
Paris
My buddy has a secondary building where the deck was attached to the floor joists and we decided to rip it down. The end of the floor joists were completely trashed by carpenter ants. I figure that deck had about 1-2 more years before it fell down.

I agree with everyone else... this deck is so small Id tear it down and start over. It would actually be easier.
For sale: Ego 56V 5aH batteries, BNIB
https://forums.redflagdeals.com/ego-law ... h-2294293/
Deal Fanatic
May 29, 2006
9671 posts
2334 upvotes
some of those boards look like they are not even attached to anything. the double joist 3rd in from the front, appears to be sitting on maybe 1/2 inch of a concrete foundation. I see no posts holding this structure up either.
Deal Expert
User avatar
Dec 26, 2005
16561 posts
1563 upvotes
Thornhill
They’re just attached to the ledger. I don’t even see hangers. It’s not even built to code. I’d remove it all and start over.

bjl
What we do in life echoes in Eternity... and in Google cache.
RFD discounts for Schluter products
Deal Addict
Nov 27, 2013
1166 posts
1261 upvotes
I don't even know how this is holding up. Tear down and start fresh with a proper ledger board.


I wouldn't stand on that deck
Deal Fanatic
User avatar
Oct 19, 2008
6202 posts
1804 upvotes
Whitby
t3359 wrote:
Aug 7th, 2019 11:45 am
They’re just attached to the ledger. I don’t even see hangers. It’s not even built to code. I’d remove it all and start over.
There is no ledger board.
The deck joists run inside the house, they are sistered to the house floor joists.
Deal Expert
User avatar
Dec 26, 2005
16561 posts
1563 upvotes
Thornhill
Zamboni wrote:
Aug 7th, 2019 1:29 pm
There is no ledger board.
The deck joists run inside the house, they are sistered to the house floor joists.
Oh hahaha. I thought I saw a ledger board there.

So the builder hacked holes into the brick veneer?

bjl
What we do in life echoes in Eternity... and in Google cache.
RFD discounts for Schluter products
Deal Addict
Nov 27, 2013
1166 posts
1261 upvotes
Zamboni wrote:
Aug 7th, 2019 1:29 pm
There is no ledger board.
The deck joists run inside the house, they are sistered to the house floor joists.
I think its the actual floor joists that extend 5 feet. I dont see how it would hold together if it wasnt the case.
Deal Expert
Aug 2, 2001
16063 posts
6226 upvotes
To answer your question about protecting the top of joists, they now market "Joist Tape" / "Deck Tape":
https://www2.lowes.ca/product/deck-tape ... ape-806107

You put this on the tops of your joists to protect them from standing water. You can also use other products of course like roofing felt, but this tape comes in the right widths (roofing felt you would have to cut).


Because you are going with piles I would assume you would leave the deck as freestanding and completely stop using the joists that extend into your home. (4) piles seems like enough to me for a freestanding 12x12 deck (https://www.joneakes.com/system/PDFs/Ou ... ations.pdf) to support (2) beams and the joists that will go on top.

Top