Deck help

Airdriedeck · #1 07-08-2018, 10:12 PM

Hi! Hoping someone can help out:
We are building an attached 14x20 deck (attached on the 14ft side)
We have been given 4 2x8x14 beams and 4 2x8x8 beams by RONA.
We are assuming that we need to attach those beams doubled up to make 2 20ft beams and cut the excess off. If so, what spacing do we need between beams and from the edge of what the deck will be? How many posts would we need?

Any insight is appreciated! Thanks so much.
Ps: we also have a 6ft ledger on the other side of the house (cornered to the 14ft ledger)
Pps: none of the plans they gave us make sense for our size of deck and materials given

CaberTosser · #2 07-08-2018, 10:30 PM

Nope nope nope. You won’t be manufacturing a 20’ beam out of 14’ joists. The probable plan would be for one of those four 14 foot joists being anchored to the house and the other three to be sistered together to make your 14’ beam that will be parallel to the house but probably about 17’ away from the house. Joists will be suspended by joist hangars attached to the ledger board at the house and then will run over top of the triple-laminated beam. Attaching the ledger board to the house has a number of important considerations such as a flashing to keep precipitation controlled and fasteners of sufficient strength and length anchored into the existing framing rather than merely the exterior sheathing.

No offence, but based on these questions I think you should have an experienced person helping or advising, or hire a professional. It will be easier than having it done again as not all of your material will be able to be re-used.

Jamie · #3 07-08-2018, 10:35 PM

Quote:

Originally Posted by CaberTosser

Nope nope nope. You won’t be manufacturing a 20’ beam out of 14’ joists. The probable plan would be for one of those four 14 foot joists being anchored to the house and the other three to be sistered together to make your 14’ beam that will be parallel to the house but probably about 17’ away from the house. Joists will be suspended by joist hangars attached to the ledger board at the house and then will run over top of the triple-laminated beam.

No offence, but based on your questions I think you should have an experienced person helping or advising, or hire a professional.

This!!!
If your in Calgary, I have a carpenter that will come and lend you a hand. Of course your going to pay him. But you will be working side by side and learning.

CaberTosser · #4 07-08-2018, 10:40 PM

I’m probably way off on the distance there, I would bet that with 2” x 8”s they won’t be 20’ long and that perhaps another beam is in order, even with a 48” cantilever over the beam that would have about 16’ span to the house and that would be a bit too long of a span, it would be rather ‘splashy’ in terms of spring and rebound. This isn’t even counting what the plans are for the footings and support columns, and what height it is off the ground. Is it low enough that guardrails are not required or is it high enough that they will be? If it is elevated then there will be specific considerations for the support columns in terms of the depth of the hole. And I’m not even a carpenter, though I am a plumber so I do have to deal with framing by knowing what can and what cannot be court out of my way

Airdriedeck · #5 07-08-2018, 11:43 PM

No offence at all...thank you for responding!
The deck is 2ft tall. The ledgers are already installed (by the builder)
We have 16 joists (2x8x14) aside from the beams listed in the original post.
I guess the question boils down to: what is the ideal spacing of the beams in this case scenario

Quote:

Originally Posted by CaberTosser

I’m probably way off on the distance there, I would bet that with 2” x 8”s they won’t be 20’ long and that perhaps another beam is in order, even with a 48” cantilever over the beam that would have about 16’ span to the house and that would be a bit too long of a span, it would be rather ‘splashy’ in terms of spring and rebound. This isn’t even counting what the plans are for the footings and support columns, and what height it is off the ground. Is it low enough that guardrails are not required or is it high enough that they will be? If it is elevated then there will be specific considerations for the support columns in terms of the depth of the hole. And I’m not even a carpenter, though I am a plumber so I do have to deal with framing by knowing what can and what cannot be court out of my way

Coyotebutcher · #6 07-10-2018, 12:19 PM

Quote:

Originally Posted by CaberTosser

I’m probably way off on the distance there, I would bet that with 2” x 8”s they won’t be 20’ long and that perhaps another beam is in order, even with a 48” cantilever over the beam that would have about 16’ span to the house and that would be a bit too long of a span, it would be rather ‘splashy’ in terms of spring and rebound. This isn’t even counting what the plans are for the footings and support columns, and what height it is off the ground. Is it low enough that guardrails are not required or is it high enough that they will be? If it is elevated then there will be specific considerations for the support columns in terms of the depth of the hole. And I’m not even a carpenter, though I am a plumber so I do have to deal with framing by knowing what can and what cannot be court out of my way

For spans and spacing you would need to consult a building code span table. Also I am a journeyman carpenter and have built many decks, and with the questions you have, I would strongly recommend a proffesional

Airdriedeck · #7 07-08-2018, 11:45 PM

Thank you for the offer but I have spent all my money on the materials ha! I have someone experienced in building decks to help out but I want to figure out the post situation before they get here so I can get the holes dug and concrete poured in

Quote:

Originally Posted by Jamie

This!!!
If your in Calgary, I have a carpenter that will come and lend you a hand. Of course your going to pay him. But you will be working side by side and learning.

jpohlic · #8 07-09-2018, 06:34 AM

Rona should have supplied you with construction drawings if they sold you a deck package

Sneeze · #9 07-09-2018, 08:22 AM

Some guys (like me) earn our livings from knowing how to access and read the span tables - then design and construct functional products that work well.

I suggest paying a pro to assist you considering your question.

My advice is 2x8's at anything past a small span will be bouncy and they won't run anywhere near 20'.