Owner/builder for garage-shop build. Should I be scared?

[Fabrik8]

The only guy I know that did a SIP structure said it was equivalent to existing building/renovation work in terms of time allocation.

You'll have to explain that one, I'm lost there for context.

 

[Loganwayne]

We did some testing on sip panels when I was in college. Honestly I don’t think they are that great. Yes you can put up a wall quickly but from testing they aren’t as strong and plumbing and wiring can be a pain I believe.


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[Fabrik8]

We did some testing on sip panels when I was in college. Honestly I don’t think they are that great. Yes you can put up a wall quickly but from testing they aren’t as strong and plumbing and wiring can be a pain I believe.

There are some types of SIPs I have no desire to use, especially anything with a bonded EPS core. They definitely aren't all the same. I'm not entertaining anything but urethane.

With the urethane stuff, they just put wiring chases in before foam injection, so it's just pulling through conduit. Don't know about plumbing. Planning electrical beforehand is pretty damn important because of that.

 

[awheelterd]

The only guy I know that did a SIP structure said it was equivalent to existing building/renovation work in terms of time allocation.

I looked into them when planning my house and realized they just weren't practical no matter how much I wanted them to be.

I have two industrial buildings built with metal clad SIP and they are amazing for what they are. But they're big white buildings. They're beautiful to me, but I don't think we will be receiving any architectural design awards for them.

 

[Fabrik8]

I looked into them when planning my house and realized they just weren't practical no matter how much I wanted them to be.

I have two industrial buildings built with metal clad SIP and they are amazing for what they are. But they're big white buildings. They're beautiful to me, but I don't think we will be receiving any architectural design awards for them.

So what you're saying is that they could have been interesting if you had hired an architect?

The metal SIPs are definitely cool, but also don't seem to have the design flexibility of some of the other types it sounds like.

 

[awheelterd]

So what you're saying is that they could have been interesting if you had hired an architect?

The metal SIPs are definitely cool, but also don't seem to have the design flexibility of some of the other types it sounds like.

Lol! They were very interesting, but not practical. I got the same net effect by stick building and filling it full of foam though ha!

 

[Fabrik8]

Lol! They were very interesting, but not practical. I got the same net effect by stick building and filling it full of foam though ha!

Yeah, I'm not hung up on using them, but it would be cool. It's really going to depend on how many other expensive things I can eliminate by using them, so obviously how the relative costs stack up..

One obvious benefit to stick built is that I can do the insulation and interior finishing.....later. That's not a cost reduction though, only a cost delay.

 

[Loganwayne]

Might as well insulate it now, an insulation sub can buy and install cheaper than you can buy it


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[Fabrik8]

Am I off-base here for estimating $10 +/- psf (installed) for concrete? Somewhere close to 1200 sqft, so $12k for concrete, maybe $14k-15k to be more conservative?

I'm trying to put some numbers to various parts of the building, just as a back-of-the-napkin for build costs to figure out why the quote is so high. I've got some breakdown from the builder on where some of the big costs were besides the core building envelope (the metal roof added $8k over shingles, for example), so I'm doing some math checks. Some of the discretionary stuff added about $25k, but I'm then left with a somewhat unfinished building that is still more than I want to spend, and needs more money to finish.

Still exploring options here.

 

[Loganwayne]

450 a yard should cover your cost for materials and labor. Figure your thickness of slab and turn downs should get you in ball park. No one will quote by sf because thickness will effect cost


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[Fabrik8]

450 a yard should cover your cost for materials and labor. Figure your thickness of slab and turn downs should get you in ball park. No one will quote by sf because thickness will effect cost

Super rough math time! I'm showing this because I'm making assumptions because not a concrete guy:


30x40 with a 1 foot wide by 1.5 foot deep downturn (Google is all I'm going off of), so centerline for downturn at roughly 29x39 feet perimeter, so 136 cuft roughly.
1200sqft x 4inch slab is 360 cuft (low side), or 1200sqft x 6inch slab is 600 cuft (high side).
Add and convert to cu yards, comes out to 21 yards (low side) or 30 yards (high side).

So that's $9450 to $13500 if $450/yd. Somewhere in the middle is where it will probably be, with real-world dimensions and things like lift post footers, tapered stuff, etc.

Soooo $13k for concrete goes onto the cost sheet, conservatively.
Okay, that's a pretty solid guess if it falls somewhere in that range.

 

[Fabrik8]

In other news, SIP package for the walls is about $11k (probably slightly more), SIP roof package is $11k (coincidentally). So maybe $25k replaces most of the framing, all of the sheathing, most WRB/housewrap, insulation, roof deck, and some of the roof structure.
I don't know how competitive that is, but that would place the building envelope at $38k for SIPs and concrete. SO that would be the starting point to figure out parity with stick framing, if possible.

So then need $2500 of windows, 15 square of shingles, siding/flashing/trim, man door, garage doors, electrical. Eventually drywall to cover the interior SIP skin, and also a minisplit.
That brick wall ended up quoted at $2k.

 

[rockcity]

What was the roof cost for asphalt? Metal is usually about 30% more in my area. That means your shingle roof is about $25k and metal was an $8k upgrade? For 1200 sq ft building, that seems high.

I just did 30 or so squares on a house. 29 ga metal, felt, with trim and screws had a total cost less than $15k even with a few repairs. I’d have to check receipts to verify specifics.


And, I don’t get the idea of a thicker floor for the lift posts. It sounds good but is t as beneficial as one would think. Unless you have an independent foundation with added rebar and multiple rebar mats for that thickened area, you really aren’t doing much other than wasting $ on extra concrete. Adding thickness to concrete without adding rebar and not isolating it from the surrounding slab isn’t really going to benefit you. With thickened and turndown slabs, a bottom mat is added to compensate for the added thickness and to add strength by utilizing this additional concrete.


I would just use quality reinforcing placed adequately and increase the psi of the concrete and make the entire slab one thickness. More rebar isn’t going to hurt (unless you are stacking bars, then you create a shear plane, but in a slab, should be a non issue). And when placing, don’t let the contractor use a lot of water to make it easier to place; water weakens the concrete. We usually hold 1-2 gallons of water per yard and add as needed but rarely ever add the full amount of water; our 5,000 psi concrete regularly breaks at 6,000 psi in 3-7 days and even higher at the 28 day mark. Pours where we add all the water, we are lucky to get to 4800psi.

 

[Loganwayne]

In other news, SIP package for the walls is about $11k (probably slightly more), SIP roof package is $11k (coincidentally). So maybe $25k replaces most of the framing, all of the sheathing, most WRB/housewrap, insulation, roof deck, and some of the roof structure.
I don't know how competitive that is, but that would place the building envelope at $38k for SIPs and concrete. SO that would be the starting point to figure out parity with stick framing, if possible.

So then need $2500 of windows, 15 square of shingles, siding/flashing/trim, man door, garage doors, electrical. Eventually drywall to cover the interior SIP skin, and also a minisplit.
That brick wall ended up quoted at $2k.

Another option for sip would be conventional framing with a insulated zip panel system


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[Fabrik8]

What was the roof cost for asphalt? Metal is usually about 30% more in my area. That means your shingle roof is about $25k and metal was an $8k upgrade? For 1200 sq ft building, that seems high.

I just did 30 or so squares on a house. 29 ga metal, felt, with trim and screws had a total cost less than $15k even with a few repairs. I’d have to check receipts to verify specifics.

I don't know, honestly. I was only given the cost premium for the metal, not the starting cost of the asphalt. The $8k updgrade for standing seam seems like more than 100% above what asphalt would be. That was one of the things that kinda threw up a flag for the pricing.

I just did 30 or so squares on a house. 29 ga metal, felt, with trim and screws had a total cost less than $15k even with a few repairs. I’d have to check receipts to verify specifics.

Wut? Was that standing seam or 5V? If that scaled to half for 15 squares, that would be a much easier decision at that price.

 

[Fabrik8]

Another option for sip would be conventional framing with a insulated zip panel system


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That looks awesome (I just looked it up), but doesn't sound like enough insulation by itself. Well, maybe though, if you assume that an normal stud wall with fiberglass batt is probably less than the R-12 of the 2.5 inch insulated ZIP panel, with stud thermal bridging and all that (average R-11 for a 2x6 wall IIRC?).. Hmm.

It really is like a thin EPS SIP, but without the inner skin.

Any idea on pricing?

 

[rockcity]

I don't know, honestly. I was only given the cost premium for the metal, not the starting cost of the asphalt. The $8k updgrade for standing seam seems like more than 100% above what asphalt would be. That was one of the things that kinda threw up a flag for the pricing.




Wut? Was that standing seam or 5V? If that scaled to half for 15 squares, that would be a much easier decision at that price.

If you are doing standing seam, then you are certainly closer to double the price of asphalt. Using 5V/masterib/ag metal roof, you should only be around 30% more.

I don’t see a cost benefit for standing seam aside from a little nicer look and less risk with no exposed fasteners. But, you have to have an installer that really knows what they are doing because they can fawk it up real quick and it will look like shit.

 

[awheelterd]

Last year when building my house the shingle quote was 12k and standing seam was 21k. 1st floor is 2400sqft plus 500sqft carport. I have a fairly steep pitch so that's quite a few sqft more than house footprint.

Also, does anyone actually do only a 12" wide turn down? Most are 18-24" I thought?

 

[rockcity]

I see most turndowns as 24” or 18” because that’s the size of most mini excavator buckets. We usually increase the size of our turndowns to 24” or 18” during constructability reviews because we know most grading guys are going to use their 24” bucket. 12” buckets are for trenching.

 

[Loganwayne]

I also add somewhere between 20-30% on expected concrete usage because I’ve never had someone make every single footing, and pad being perfect


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[awheelterd]

I also add somewhere between 20-30% on expected concrete usage because I’ve never had someone make every single footing, and pad being perfect


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Yup. Everytime we have concrete laid we always have a little sidewalk or skirt somewhere formed up for that inevitable extra yard or so. I'd rather put it somewhere useful rather than watch the driver dump it in a pile or take it back to the plant.

 

[Fabrik8]

I see most turndowns as 24” because that’s the size of most mini excavator buckets. We usually increase the size of our turndowns to 24” during constructability reviews because we know most grading guys are going to use their 24” bucket. 12” buckets are for trenching.

With the 24 inch bucket and a perimeter form, where does that usually come out for dimensions? Like 18 or 20 wide, plus the chamfer where it meets the slab?

 

[rockcity]

With the 24 inch bucket and a perimeter form, where does that usually come out for dimensions? Like 18 or 20 wide, plus the chamfer where it meets the slab?

You don’t necessarily need a chamfer to meet the slab. If your concrete turn down is designed as 12” or 18” wide (but dug and poured 24”) and rebar is placed correctly for the design, the virtual designed area of the concrete Includes the chamfer; making it square just adds concrete in lieu of adding dirt and compacting and sloping, etc. The concrete cost is more but the efficiency in installation typically saves you $. And you don’t chance a sub being lazy and fucking it up. Because that work can be really tedious and more often than not, they half-ass the work and get it wrong.


Depending on your design and frost line, the sub will likely earthen form anything below rough grade and just form the top portion which is visible. No need to dig out more than necessary or use form boards for the entire depth of the footer. Some people like that but for a residence or small shop, no need. Plus, unless they dig out more than 12” beyond face of concrete, it’s going to be difficult to find compaction equipment to compact anything less than 12” wide. If the backfill in front of the form is less than 12”, chances are they are going to fuck it up because the only compaction equipment/tools I’ve seen smaller than 12” is a hand operated plate tamp. No way in hell are you going to get a concrete sub to compact that by hand and it will end up getting fucked up; you’ll only find it after a couple good hard rains long after the concrete sub has left site.

 

[jeepinmatt]

Concrete for my 34x40 shop was $3/sqft finished including labor and material in 2013. And they augered 14 post holes, set, leveled, and braced the 6x6x16s. And set the wire and rebar that I supplied for free. Total for a 34x40 was $6500. Even includes finish grading and gravel under slab, and 2 loads of gravel for the driveway and parking area.

Welcome to Charlotte 2020.

 

[Fabrik8]

Concrete for my 34x40 shop was $3/sqft finished including labor and material in 2013. And they augered 14 post holes, set, leveled, and braced the 6x6x16s. And set the wire and rebar that I supplied for free. Total for a 34x40 was $6500. Even includes finish grading and gravel under slab, and 2 loads of gravel for the driveway and parking area.
View attachment 310594
Welcome to Charlotte 2020.

Yeah, that's not fair.