My garage vision: yay or nay?

[lukeiam]

I was laid off this year and I'm trying to look at it as an opportunity. I work in coaching and athletic training and I could really use a space to work (with clients) out of. Originally, I envisioned this as a possible ADU because my inspector friend loved the idea...But the reality is that it would be cheaper to raze this thing to make it code and living in this box would confine me to bachelorhood for life! Hahaha. Some day I could do an ADU in my backyard.

All said, I want to go the cheaper route on this. The expensive route would be raising it and pouring a whole new slab, etc, but that's just unnecessary, I think. The structure is SOLID, as are the sils and footer (there appears to be a separate/original concrete footer under the sil; I assume they just poured a slab inside it).

Anyway, this is my plan:

-- Jack up the structure using the existing floor on the inside and doing a) one course of concrete block or b) laying 8x8 PT or bigger under the sils all the way around. The structure is at at grade (far side it's a bit over grade) so it really should be off the ground if I'm going to insulate.

-- I considered insulating from the outside and siding over, but that's probably a no-no. The bays are proper 2x4, so actual 4 inches depth, old growth. So I could insulate the bays, probably Rockwool, and drywall over. I could wrap the outside (that's how my house is done). I would obviously side it either way.

-- I would add a subpanel inside and probably 220 with 2-3 outlets and overhead light.

-- The rafters are also 2x4s, unfortunately. I could pad that out to a proper 6" depth and insulate and drywall over. It's a hip roof; I wish it were a shed or gable roof. The structure's floor is 18x18' and the ceiling is quite high (walls are 9'), but I wouldn't want to create a ceiling -- it would be too cramped/small for a gym space. Would this work? Or could I use ventilation or something else to get air flow?

-- The floor I would just leave the concrete and lay down plastic and build like I were doing an insulated structure over piers -- 2x6s across, insulate inside, OSB for subfloor, maybe someday do a wood floor on top. I'd remove the garage doors and find a used sliding door somewhere and install it. Ultimately, this may be more expensive than jacking out the old concrete and doing insulation/rebar/concrete pour. I would be curious of thoughts on this?

-- for heat/cooling I would probably just use a wall unit for summer and either baseboard electrical or I even considered just a very small tiny home-style wood stove in the corner....this doesn't need to be kept piping hot in winter as it'll be a gym space.

This garage is next to a duplex I own, which I've renovated with several carpenter friends. I'm not expert, but I'm plenty skilled, and any help I need I can grab from friends in the trades.

I really appreciate your reading this and any thoughts/help you could provide! Ultimately, I'm just trying to make a space I could work out of without breaking the bank and giving me some job protection.

 

[racecougar]

A. Location?
B. Intended internal temps in Summer/Winter? All of the time or part time?
C. No roof venting currently, correct?

 

[lukeiam]

A. Location?
B. Intended internal temps in Summer/Winter? All of the time or part time?
C. No roof venting currently, correct?

Good points!

a) I'm in Massachusetts
b) I'd say tolerable in winter, so like 60...Again, it'll be mostly a gym or workspace. In summer (July/Aug) times I'd probably only use it before noon or at night after 4/5pm, not when the sun is overhead and it's hot. Even now, totally uninsulated, it's fine before 10am on the hottest days. And at night it's not bad at all.
c) No venting now!

Thanks for the Qs!

 

[racecougar]

If you only intend to heat/cool the building part time (didn't answer that question), I'd be concerned about indoor humidity.

I'd spend some time analyzing span charts, with a mind toward the rafter loading (don't forget snow load!) before deciding the dead load capacity. While the span isn't very large here, we're only working with 2x4" rafters. Additionally, a hot roof design isn't great, but I understand that you do not want to frame out an actual ceiling and lose headroom.

If you're planning to keep the punching bag attached to the roof, it needs to be accounted for in your load calcs. I'm not sure what the live load would be for that; you'll need to research it.

 

[lukeiam]

If you only intend to heat/cool the building part time (didn't answer that question), I'd be concerned about indoor humidity.

I'd spend some time analyzing span charts, with a mind toward the rafter loading (don't forget snow load!) before deciding the dead load capacity. While the span isn't very large here, we're only working with 2x4" rafters. Additionally, a hot roof design isn't great, but I understand that you do not want to frame out an actual ceiling and lose headroom.

If you're planning to keep the punching bag attached to the roof, it needs to be accounted for in your load calcs. I'm not sure what the live load would be for that; you'll need to research it.

Thanks. Good points! The roof is a weak point given the rafter depth. I'd almost tear it out then start over, but then you're totally in the weeds of just doing the whole thing over. This is why I was thinking of at least padding it another 2" for insulation purposes.

I wouldn't be hanging anything from the roof -- the punching bag is just on some cross-beam support, not a rafter.

I think this is all where I get messy in my thinking, because if I'm starting to make major structural changes, the Q becomes: should I just tear the thing down and prop up an 800 sqt ft ADU over its footprint. That is, if I can't get away with something functional with the existing structure.

I built a home addition last year on piers in Vermont and the design would basically the same for framing an ADU.

 

[racecougar]

I wouldn't be hanging anything from the roof -- the punching bag is just on some cross-beam support, not a rafter.

Insulation, furring/framing, and drywall has considerable weight. It needs to be accounted for.

That "cross-beam support" is a rafter tie; it isn't intended to carry any vertical loading (really shouldn't have a punching bag hanging from it).

 

[lukeiam]

Insulation, furring/framing, and drywall has considerable weight. It needs to be accounted for.

That "cross-beam support" is a rafter tie; it isn't intended to carry any vertical loading (really shouldn't have a punching bag hanging from it).

Thanks. It's not a rafter tie. It's cross beam support for the garage door and the load spans the top plates on either wall...anyway, speaking of rafter ties, that would be a way to support the ceiling should I add drywall / insulation. I could also use lighter material to hold the drywall, like beadboard, etc.

 

[carlaisle]

You don't sound like you're overly concerned about the heating/cooling aspect, so I wouldn't waste the time/expense on padding the roof just to add insulation. Getting the wood farther away from the ground and increasing the ceiling height are all good (especially for a training space) but jacking the building up to add a a single layer of block sounds inefficient at best. For what you want, it sounds like a tear down and rebuild would be the most practical path to success.

Don't you need a permit to install a flower pot most places in Taxachusetts? You might want to check into what whomever needs to sign off on your plans is willing to let you do.

For a gym space, I would think a bathroom would pretty much be mandatory. It certainly won't fit the definition of an ADU in most areas of the country without one.

Speaking just for myself, if I showed up to a training session and the venue didn't have AC I'd walk.

 

[firebirdparts]

Sounds cheap and easy enough to me. I am lazy, so I would probably not jack the building up. Just deal with the consequences of not.