Yet another 30x40 Shop/Cave

[Cuda416]

Yup, another 30x40(ish) from another lurker, finally in a position to build a garage. New (to me) property, 1.5 acres, wife is totally on board, no permits required, seemingly lax HOA, doesn't have to match the house (though I'll try to make it somewhat close) and they don't like metal buildings I am told (not sure about pole buildings) and two 200A panels on the house to pull power from. I probably need to go buy a lotto ticket right about now...

The intended use is mainly to work on cars, and maybe keep a trailer/boat under an extended roof off the side. Though I'd like a small office (which I can frame in later) and a mezzanine or loft for storage as well. What I've read so far says build BIG. While I agree with that, property taxes in TX are such that its going to cost me around 400-500/yr for something this big. Note, I've not contested the property assessment, yet but if I can I will. I cannot however plan on that happening so I am going with the worst case. The county folks say I can calc the taxes with (cost_to_build/100)*tax_rate. I am assuming the tax_rate is the overall tax rate of 1.81, which feels like getting beat about the head and shoulders with a hammer but hey, no income tax right?... ugh...

Questions I still have for the county (taxes) have to do with driveway stuff such as do they tax a concrete driveway/(un)covered pad, or just "structures" with concrete floors. I've heard of counties doing that which sounds bizarre but hey, I'm no tax collector and clearly don't understand why my non-living-space building is getting taxed anyways so....

Anyway, point is, I am trying to be fiscally responsible but at the same time, get as much bang for my buck as possible. I'll try to do as much as possible myself. I work cheap right?

My biggest question so far, as seems to be the case with others, has to do with the cost of the slab. I believe it will be a monolithic, 4 inch thick, rebar/wire mesh, vapor barrier at the very least. Maybe a bit thicker where the lift goes. I had one contractor tell me 10-12k, but I believe he is a GC, so maybe taking a cut on top, not sure.

I'll pull power from one of the two 200A panels on the house, probably 100A to cover running my compressor, welder(s), lift and other smaller items like lighting (LED based) etc.

Also might shove a receiver into the slab/pad on the outside to lock down a trailer etc. Saw that in another build thread and thought "Genius!" so I'll do that too.

The work will be done in Castroville TX, just outside of the city limits (no permits, unless I want a restroom) and I'm not in a flood plane so the county just want's their "fair share" of what I build...

1. What should something like this cost?
2. Who does site prep, the concrete folks, or do I get someone else to do that?
3. Does anyone have any recommendations for both?
4. What other things need I consider?

Feel free to blast my plan into the dirt and offer alternative suggestions (it will happen regardless but hey). Any guidance will be greatly appreciated.

 

[Falcon67]

Questions I still have for the county (taxes) have to do with driveway stuff such as do they tax a concrete driveway/(un)covered pad, or just "structures" with concrete floors. I've heard of counties doing that which sounds bizarre but hey, I'm no tax collector and clearly don't understand why my non-living-space building is getting taxed anyways so....

Because Texas taxes property improvements. All property improvements. Except maybe a garden shed. They will tax the building based on it's estimated value. If they are anything like Taylor County, then save your receipts for the project and if they value it more than what you spent, you file a protest after you receive your yearly tax assessor value notification, sticking to the time limits allowed - IIRC, before May 1. It's not a war, Texas requires assessors to work at appraising property on as fair and close to market as possible, with clear options for the property owner to contest the valuation. An easy process, really.

>1. What should something like this cost?
Depends - on more than anyone here can guesstimate. A lot depends on your soil, I'd assume - maybe wrong - that west of San Antonio you have rocky soil so I'd check with San Antonio about recommendations

Here - Terrell Hills, starts on page 5 give you hints you need to know: http://www.terrell-hills.com/CONSTRUCCh.3.pdf "G. Small Buildings and Residential Beam and Slab Foundations:" I doubt that Castroville is much different.

>2. Who does site prep, the concrete folks, or do I get someone else to do that?
Unless you find a concrete company that also does site prep, it'll be two separate operations. Most concrete companies just deliver and set. If you feel like being the "GC" you can shop the separate operations and get the required inspection by Bexar County before and after the pour. You'd likely need set of engineered plans to direct the operations of both crews. Hiring a GC gets you out of that, but costs more. Sometimes a lot more.

 

[OneOfEm]

My biggest question so far, as seems to be the case with others, has to do with the cost of the slab. I believe it will be a monolithic, 4 inch thick, rebar/wire mesh, vapor barrier at the very least. Maybe a bit thicker where the lift goes. I had one contractor tell me 10-12k, but I believe he is a GC, so maybe taking a cut on top, not sure.

It's never apples to apples, but here's what I've found:

I'm at the beginning of a 44x50 pole building build. I've poured the post piers and I'm getting ready for the slab. The total concrete cost for 47 yards will end up at just under $5500.

I had one guy quote doing all of the site prep (remove a couple of stumps and topsoil; backfill/smooth; dig footers; install vapor barrier/rebar/mesh) and the pour, and he bid $14/SF for everything but the concrete.

I switched gears and had three other folks quote just the pour/finishing. Their quotes ranged from $5/SF to $2/SF.

So, at $2/SF + $5500 + some equipment rental + rebar/mesh/chairs/vapor barrier, I'm up to around $11,000 with me doing almost all of the work.

Yours is a bit more than half of the size of mine, so perhaps your estimate is right.

 

[73RR]

From my experience, I'd say calculate the cost of the concrete and then also use that for labour costs. 'Most' of the time labour and materials are about 50/50. Not exact science but a ballpark. A 30x40 mono with turned down footings will use about 25-30 cubic yards. What is the local price for a 5-sack mix?
Site prep is, obviously, a separate line item. Some concrete guys do their own and others won't. Just make sure it is right as it will affect the finished slab. Call around, talk with 'excavators'.
If you want the power to land inside the shop then you need to trench for and lay in your conduits during/after the sight prep. Always lay an extra pipe while your there; easier than trying to do it later. If the run is long then consider using a BIG conduit as it will make pulling cable a lot easier. I'd also toss a water line in the trench just in case the need arises.
Others will opine as to their methodology.

 

[Cuda416]

Because Texas taxes property improvements. All property improvements. Except maybe a garden shed. They will tax the building based on it's estimated value. If they are anything like Taylor County, then save your receipts for the project and if they value it more than what you spent, you file a protest after you receive your yearly tax assessor value notification, sticking to the time limits allowed - IIRC, before May 1. It's not a war, Texas requires assessors to work at appraising property on as fair and close to market as possible, with clear options for the property owner to contest the valuation. An easy process, really.

That's great to know. I've never had to deal with this before, in any state. I do believe the world works on relationships and so I try to make good with those folks. In my last place, the town inspectors, electrical and plumbing, were extremely helpful and professional. As far as I am concerned, they are my best resources during a project that has to pass inspection.

Here - Terrell Hills, starts on page 5 give you hints you need to know: http://www.terrell-hills.com/CONSTRUCCh.3.pdf "G. Small Buildings and Residential Beam and Slab Foundations:" I doubt that Castroville is much different.

Extremely helpful, thanks!

>2. Who does site prep, the concrete folks, or do I get someone else to do that?
Unless you find a concrete company that also does site prep, it'll be two separate operations. Most concrete companies just deliver and set. If you feel like being the "GC" you can shop the separate operations and get the required inspection by Bexar County before and after the pour. You'd likely need set of engineered plans to direct the operations of both crews. Hiring a GC gets you out of that, but costs more. Sometimes a lot more.

Again, very helpful knowing the difference of responsibilities.

Thanks for the info OneOfEm, Now I am trying to understand sizing of the footings, which seem to be called "beams" in the PDF Falcon76 shared, unless I am reading things wrong. Looks like for over 30 feet in any direction and they need to be 30 inches wide and 6 inches deep? Not sure what the short "wall" that the slab sits on top of is called but how does that get sized? just trying to understand the math.

If you want the power to land inside the shop then you need to trench for and lay in your conduits during/after the sight prep. Always lay an extra pipe while your there; easier than trying to do it later. If the run is long then consider using a BIG conduit as it will make pulling cable a lot easier. I'd also toss a water line in the trench just in case the need arises.

Looks like #4 copper in a 1.25" conduit is min for 100A but I'll probably size it for 200A and bump the specs a bit (and leave a chord in it), how deep do they need to be in TX? I have no idea what to do about a water line. If I have a bathroom , I am required to get a permit and hire someone to connect it to the septic system per the county I believe, which makes sense.

This is all great info, I really do appreciate it.

 

[nes999]

You could wait until everything is finished to do concrete and electrical it will drastically lower the accessed value. So you could save on some property tax.

Around where I live the concrete is typically poured after the fact and the concrete guys just board odd your garage door and pour.

Sent from my VS988 using Tapatalk

 

[My Old Tools]

Our county has a stock formula for out buidings/metal buildings. It is SF based and it is no where near the building cost. That's fair because you never get the building cost when you sell.

Around here a 30x40x12 on a flat lot, 6/12 pitch, slab with perimeter and cross beams, red iron I-beam frame, C-channel purlins, metal covering, 3" insulation, 12x12 overhead door, man door, 4 windows, 20x30 loft, will cost you about $33,000. Add a heavily sloped lot, lots of dirt work and fill, more concrete for stem walls, more windows, overhead beam for a hoist, 16x20 driveway, 40x12 open lean to on one side, and you are approaching $60,000. Those are recent quotes.\

Both of those are unfinished inside, roughed in plumbing for a half bath, and no electrical. Includes all site prep, dirt work, and removing a few trees.

You can run 90 amps with 2-2-2-4 mobile home feeder as long as the run is under about 200 feet. You'll need a 2" minimum conduit for aluminum. Bigger is better.

 

[Cuda416]

You could wait until everything is finished to do concrete and electrical it will drastically lower the accessed value. So you could save on some property tax.

Around where I live the concrete is typically poured after the fact and the concrete guys just board odd your garage door and pour.

Sent from my VS988 using Tapatalk

That might be an option if I go with a pole building. Thanks

 

[Cuda416]

Our county has a stock formula for out buidings/metal buildings. It is SF based and it is no where near the building cost. That's fair because you never get the building cost when you sell.

Around here a 30x40x12 on a flat lot, 6/12 pitch, slab with perimeter and cross beams, red iron I-beam frame, C-channel purlins, metal covering, 3" insulation, 12x12 overhead door, man door, 4 windows, 20x30 loft, will cost you about $33,000. Add a heavily sloped lot, lots of dirt work and fill, more concrete for stem walls, more windows, overhead beam for a hoist, 16x20 driveway, 40x12 open lean to on one side, and you are approaching $60,000. Those are recent quotes.\

Both of those are unfinished inside, roughed in plumbing for a half bath, and no electrical. Includes all site prep, dirt work, and removing a few trees.

You can run 90 amps with 2-2-2-4 mobile home feeder as long as the run is under about 200 feet. You'll need a 2" minimum conduit for aluminum. Bigger is better.

Thanks, in Medina, I was told they do it based on the "cost" of construction. I just hope they don't perceive my labor as high cost. I'll definitely keep all of my receipts etc to show the assessor if their numbers are higher than mine.

 

[rburke65]

Concrete folks may or may not do site prep. If they don't then they are somewhat isolated for the results....." We didn't do the base prep." But be aware that the final quality will depend on the quality of the site preparation, drainage, base compaction under the floor, elevation of the slab, ...etc. Do not skimp on the "stuff" you can't see.

 

[Cuda416]

Concrete folks may or may not do site prep. If they don't then they are somewhat isolated for the results....." We didn't do the base prep." But be aware that the final quality will depend on the quality of the site preparation, drainage, base compaction under the floor, elevation of the slab, ...etc. Do not skimp on the "stuff" you can't see.

Thanks, I totally agree skimping on the foundation is not a good idea. That's the main reason it's not something I want to try doing it myself

Doing more research, looks like TX doesn't freeze like places I've lived before so I believe what is needed here will be a "slab on grade"?

 

[My Old Tools]

Texas doesn't have frost heave, but most of Texas has highly dynamic soils, i.e. they move a lot with rain and dry cycles. Be sure your foundation guy knows the soils in your area and how to handle them. For many areas that means a grade beam that is 16x16 or larger around the slab.

 

[Cuda416]

Texas doesn't have frost heave, but most of Texas has highly dynamic soils, i.e. they move a lot with rain and dry cycles. Be sure your foundation guy knows the soils in your area and how to handle them. For many areas that means a grade beam that is 16x16 or larger around the slab.

Thanks for the info. I spoke to a concrete guy yesterday who can handle everything up to the pour. While talking to him he mentioned having two cross beams as well as a center beam. At first it seemed a little excessive for a 30x40 slab but then I remembered I have no idea what I am talking about .

Around here I haven't seen much mention of using cross beams etc. so I am curious what people think of them especially in Medina county TX. The site the shop will be on is pretty flat if not dead flat already. It used to be farm land so I'm not sure of the general composition (stone/dirt/whatever) yet. The house itself, is slab on grade and has only experienced minor hairline cracks over the 10 years since it was built.

I am not opposed to beams in any way shape or form (no pun untended) but if don't need them, why have them. That said, an inadequate foundation is an expensive mistake to make.

Thoughts from anyone?

 

[My Old Tools]

My current shop is on a flat lot with fairly sandy soil, not much reactive clay. It got full perimeter beams and cross and center beams. You only get one shot to do it right so over build.

 

[73RR]

Looks like #4 copper in a 1.25" conduit is min for 100A but I'll probably size it for 200A and bump the specs a bit (and leave a chord in it), how deep do they need to be in TX? I have no idea what to do about a water line. If I have a bathroom , I am required to get a permit and hire someone to connect it to the septic system per the county I believe, which makes sense.

This is all great info, I really do appreciate it.

As others have mentioned, bigger is better. Although a 1¼" pipe will work, depending on the length of the run, it could be a real PITA to pull through and there will be little room for anything else. I would not use anything less than 2" and would probably use 3"....and have a spare pipe laying next to it. If you already own the 1¼ pipe then use it for low voltage stuff.
The cost of Carlon conduit is very small compared to the building or the cost to open the trench to install another run for some other use. The trench is open, make use of the labour. And, always leave a pull rope in every conduit you bury.

 

[Cuda416]

My current shop is on a flat lot with fairly sandy soil, not much reactive clay. It got full perimeter beams and cross and center beams. You only get one shot to do it right so over build.

+1!

 

[rburke65]

PVC conduit is inexpensive. I would not be placing anything smaller than 2" conduit for a feed. Most folks talk experience on this site......it's free.......take it. Don't forget a spare...or two. Cat cables, Internet...?

 

[Cuda416]

Most folks talk experience on this site......it's free.......take it.

That is why I am here!

 

[My Old Tools]

Yep, you can put 2-2-2-4 mobile home feeder through a 2" with reasonable bends. I was not successful getting it through 1.5" with the last couple of bends.

 

[Cuda416]

Yep, you can put 2-2-2-4 mobile home feeder through a 2" with reasonable bends. I was not successful getting it through 1.5" with the last couple of bends.

Excellent, thanks!

 

[Cuda416]

So after getting loads of advice on foundations and such, I've begun drawing up some plans for the actual garage.

It occurred to me, when laying out the walls, a 40 foot wall, with studs 16" on center, actually comes out to 40'-1 1/2". So either I am doing something wrong (very likely) or is the way to deal with it is to "short" the last stud by 1.5 inches?

Even taking away 1/2" from each end to account for sheathing, it's still 1/2" off in total length. What am I missing? What is the "proper" way to layout a floor/framing plan?

 

[laurie71]

The first and last stud should be inset 3/4". Your on-center measurements for all the other studs should be pulled from the end of the sill plate / far side of the outside stud, not from its center.

Another way to visualize it: lay out the first stud so its center is over the end of the sill plate, lay out all the studs 16" apart from that starting point, then move the layout for the first and last stud inboard by 3/4" so they are aligned to the ends of the sill plate.

It'll probably make more sense once you draw it out and see the result!

 

[Cuda416]

The first and last stud should be inset 3/4". Your on-center measurements for all the other studs should be pulled from the end of the sill plate / far side of the outside stud, not from its center.

Another way to visualize it: lay out the first stud so its center is over the end of the sill plate, lay out all the studs 16" apart from that starting point, then move the layout for the first and last stud inboard by 3/4" so they are aligned to the ends of the sill plate.

It'll probably make more sense once you draw it out and see the result!

Ok, that actually makes sense now. I thought I was doing something wrong in some complicated way. The 1.5" between the two end pieces makes the math work for me. Thanks again!