[gizzygone]

Our shed is rotting away, so it’s time for a new one. I’m considering a lean-to shed design to attach to our garage.

I know it’s typical to use PT for sheds: but at some point I’d like to add an access door from the lean-to into the garage.

However: PT isn’t for use in “dwellings”

I’m curious what you’d do?

Or: is my only choice here building a foundation and adding an addition to the garage?

 

[Nealtw]

Our shed is rotting away, so it’s time for a new one. I’m considering a lean-to shed design to attach to our garage.

I know it’s typical to use PT for sheds: but at some point I’d like to add an access door from the lean-to into the garage.

However: PT isn’t for use in “dwellings”

I’m curious what you’d do?

Or: is my only choice here building a foundation and adding an addition to the garage?

If you attaching it to the garage you do want a good support system like a foundation of piers with good footing.
Not sure the same rules apply to the newer mainly copper treatment the use.
Anything below the sub floor would be considered outside the envelope I think.
A detached garage would not be considered living space.

 

[gizzygone]

Our shed is rotting away, so it’s time for a new one. I’m considering a lean-to shed design to attach to our garage.

I know it’s typical to use PT for sheds: but at some point I’d like to add an access door from the lean-to into the garage.

However: PT isn’t for use in “dwellings”

I’m curious what you’d do?

Or: is my only choice here building a foundation and adding an addition to the garage?

If you attaching it to the garage you do want a good support system like a foundation of piers with good footing.
Not sure the same rules apply to the newer mainly copper treatment the use.
Anything below the sub floor would be considered outside the envelope I think.
A detached garage would not be considered living space.

Thank you for the reply:

My thought was to pour piers/footers and attach a ledger to the garage. I’d build a deck out of pressure treated joists and plywood, and then frame it up.

I’d have to come up with some sort of flooring, though: as I know you can’t floor over PT: so perhaps a1/4 plywood subfloor would solve that issue.

Option two: dig out a trench: pour a footer, and then build a block foundation, followed by a poured slab.

Issue here is I’m looking at a 8’x20’ shed: so the amount of extra work would be significant

 

[Nealtw]

Thank you for the reply:

My thought was to pour piers/footers and attach a ledger to the garage. I’d build a deck out of pressure treated joists and plywood, and then frame it up.

I’d have to come up with some sort of flooring, though: as I know you can’t floor over PT: so perhaps a1/4 plywood subfloor would solve that issue.

Option two: dig out a trench: pour a footer, and then build a block foundation, followed by a poured slab.

Issue here is I’m looking at a 8’x20’ shed: so the amount of extra work would be significant

Why can't you use plywood over treated joists? Just have to use HDG nails or screws.

How far off the ground would be?

 

[gizzygone]

Thank you for the reply:

My thought was to pour piers/footers and attach a ledger to the garage. I’d build a deck out of pressure treated joists and plywood, and then frame it up.

I’d have to come up with some sort of flooring, though: as I know you can’t floor over PT: so perhaps a1/4 plywood subfloor would solve that issue.

Option two: dig out a trench: pour a footer, and then build a block foundation, followed by a poured slab.

Issue here is I’m looking at a 8’x20’ shed: so the amount of extra work would be significant

Why can't you use plywood over treated joists? Just have to use HDG nails or screws.

How far off the ground would be?

It’d be close to the ground: about 8-10 inches depending on how low I can place the beam.

I suppose I could use standard plywood: but I was afraid of the lack of airflow under the structure.

 

[Nealtw]

It’d be close to the ground: about 8-10 inches depending on how low I can place the beam.

I suppose I could use standard plywood: but I was afraid of the lack of airflow under the structure.

Instead of a beam you could do a 2 or 3 ply rim with hangers, For a shed if you shape the dirt below first, air flow is not as important as you don't have all the water dripping thru deck boards.

 

[gizzygone]

It’d be close to the ground: about 8-10 inches depending on how low I can place the beam.

I suppose I could use standard plywood: but I was afraid of the lack of airflow under the structure.

Instead of a beam you could do a 2 or 3 ply rim with hangers, For a shed if you shape the dirt below first, air flow is not as important as you don't have all the water dripping thru deck boards.

Interesting: this is something I had considered: but wasn’t sure if it’d be “code”?

So essentially the beam would become a second “ledger”, so to speak, letting me get closer to the ground? Does it affect the ability to support a roof?

Obviously concrete would be the way to go here; but building a new foundation is cost prohibitive.

I want this to be a structure that holds up as long as possible. The shed is about 20 years old: and the plywood walls are rotting through, along with a few holes in the floor (thanks to field mice)

 

[Nealtw]

Interesting: this is something I had considered: but wasn’t sure if it’d be “code”?

So essentially the beam would become a second “ledger”, so to speak, letting me get closer to the ground? Does it affect the ability to support a roof?

Obviously concrete would be the way to go here; but building a new foundation is cost prohibitive.

I want this to be a structure that holds up as long as possible. The shed is about 20 years old: and the plywood walls are rotting through, along with a few holes in the floor (thanks to field mice)

A 2 or 3 play rim joist is also a flush beam, flush with floor joist.

A flush beam, also known as a header beam, is a structural component that is located at the same level of ceiling joists and one that utilizes joist hangers for attachment. It is often used for framing deck forms like octagons, or for stair landings where a cantilevered beam is not the most sensible option.Jul 17, 2017​

 

[ktownskier]

You can also use 3/4" PT plywood as the floor if you are concerned about rot from below, then cover it with a 1/2" cdx plywood for your subfloor.

Will you leave the exterior siding in place or remove it?

Is the garage attached or detached?

I know you want to add a door or two to allow access but if you treat it as an exterior room added to a garage does that change anything from a code perspective? Either Canadian or US?

 

[gizzygone]

I’ve considered this also: but I can’t find a clear answer on whether or not the plywood could be placed directly on PT, or if I needed a barrier between the two.

I’d likely remove the siding on the garage, in order to better utilize the space (cabinets).

I suppose it’d be more of an “addition” than a “lean to” in that regard.

Garage is attached to the house: but completely unfinished.

Not sure how that will affect code? I’d be interested to hear what others have to say.

 

[Nealtw]

I’ve considered this also: but I can’t find a clear answer on whether or not the plywood could be placed directly on PT, or if I needed a barrier between the two.

I’d likely remove the siding on the garage, in order to better utilize the space (cabinets).

I suppose it’d be more of an “addition” than a “lean to” in that regard.

Garage is attached to the house: but completely unfinished.

Not sure how that will affect code? I’d be interested to hear what others have to say.

You won't find anything about the plywood and pressure treated because there is no problem.

 

[gizzygone]

I’ve considered this also: but I can’t find a clear answer on whether or not the plywood could be placed directly on PT, or if I needed a barrier between the two.

I’d likely remove the siding on the garage, in order to better utilize the space (cabinets).

I suppose it’d be more of an “addition” than a “lean to” in that regard.

Garage is attached to the house: but completely unfinished.

Not sure how that will affect code? I’d be interested to hear what others have to say.

You won't find anything about the plywood and pressure treated because there is no problem.

No problem attaching directly to each other?

I saw some posts saying to put felt in between and what-not

 

[Nealtw]

No problem attaching directly to each other?

I saw some posts saying to put felt in between and what-not

You can buy treated plywood, it won't hurt it. You are mixing it up with the tape they put on joists for decks to protect them from water and dirt that get stuck between deck boards.