Garage addition....what to expect$$$

[The Juggernaut]

I wanted to add a 20x20 addition to the back of my 24x20 detached garage.
Basically slab, 3 walls and a roof. One wall will have a 8ft garage door opening.
No interior work
No drywall
No electrical
No door on 8ft opening
I priced material out at roughly $3200
Concrete cost with forms and rebar at roughly $1600

What is reasonable labor cost
Location Houston area

 

[The Cobbler]

depends entirely on your area I would say. I paid $1,000 lab to frame my 400sqft detached garage

 

[The Juggernaut]

The way I remember it labor was about equal to material cost.
Obviously that would depend on what you are doing. Kitchens and bathrooms will usually have more material cost
My thought was $10-11k for the work described.
The drywall work, electrical work and the Garage door and install would be in addition to that and left on me

 

[bczygan]

Get some bids and you will know.

At least as much as material, but more for a small job like that,

 

[The Juggernaut]

Called out multiple contractors. Over half never even came out. 3 showed up took measurements and then never to be heard from again
Have 1 bid that is stupid high at $20k
My theory is that there is soooo much work in the area, nobody wants to do it.

On the house we are Having a roof put on and new Windows installed.
Windows were stupid expensive to do turn key
Ordering the Windows from a box store (basically same Windows) and doing brother in law deal for installation for 20% the price of the turn key company

When a company quotes me $20k for 400sq foot, and I see guys on here get 30x50 metal buildings for 30k, makes me wonder WTF

Looking at just having the slab poured and possibly doing the rest myself.....with help

 

[bczygan]

Well, you can't get blood out of a turnip, so if you have made a diligent search for contractors, then you have to explore other options.

BTW, was that bid including materials?

So look into hiring experienced labor for each trade and you act as GC.

How did you search for contractors? There is an art to it. Just using the phone book won't work.

Have you hit the local job sites?

Also, if you get additional bids that are similar, then that is the price. $50/SF doesn't sound bad. Was the bid itemized with material quantities? Did you do an estimate and price materials? Get bids for each trade.

People are busy now and not enough help. They will take only the best jobs. You may not get any more bids or return phone calls. Need to go out and develop a relationship with someone. It's who you know.

And if you can get a concrete guy to do his work, why not build it yourself. I would. It's like having a side job and getting paid with what you save. And if market price is 10K for labor right now, then that is what you are getting paid! You and brother in law.


Bill (Estimator)

 

[Homerr]

I just posted this to another thread: http://www.costtobuild.net/

 

[Smoker]

You'll pay more than $1600 for concrete in my estimation. I would plan on doubling your estimate for that, especially if someone else is finishing it. Plan on roughly $25/sqft interior totally unfinished and budget for that. It soon adds up, lumber, sheathing, trusses, shingles etc.

 

[bczygan]

I just posted this to another thread: http://www.costtobuild.net/

$24,600 using that.

 

[SteveL]

Make sure you factor in enough to tie the new floor slab in to the old! I added on to mine 12 years ago and didn't think of this and now have a lip where the two meet at one end of the slab. Either the new shifted up or the old sank. Not sure which but sure would have liked to have added rebar drilled in to the side of the old slab before pouring.

I also think you are a little short on your concrete estimate if done right. I would likely double that for around here.

 

[The Juggernaut]

Make sure you factor in enough to tie the new floor slab in to the old! I added on to mine 12 years ago and didn't think of this and now have a lip where the two meet at one end of the slab. Either the new shifted up or the old sank. Not sure which but sure would have liked to have added rebar drilled in to the side of the old slab before pouring.

I also think you are a little short on your concrete estimate if done right. I would likely double that for around here.

The way I am doing the math
Please let me know if I am making a mistake
20x20x6 thick which is 200 cubic feet
24"x24" footing x 56 liner foot 112 cubic feet
312 cubic feet divided by 27 equals almost 12 cubic yards
Concrete is $105 a cubic yard so $1260
Figured $300 for lumber and rebar.

Was definitely planing to put pins or rebar into old slab to keep them from shifting
Thanks to all who have given input, please continue to do so

 

[SteveL]

I was assuming that you would hire the labor out but if you plan to do it all yourself, your numbers are not that out of line.

 

[ssdave]

Here's how I think a general contractor will bid it, rough numbers for an urban area:

Looking at it after I posted, I left off the roof sheathing, which would add $200 or so more.

 

[ssdave]

Updated my cost sheet for what I'd guess at for doing it yourself, except for the concrete:

 

[boiler7904]

The way I am doing the math
Please let me know if I am making a mistake
20x20x6 thick which is 200 cubic feet
24"x24" footing x 56 liner foot 112 cubic feet
312 cubic feet divided by 27 equals almost 12 cubic yards
Concrete is $105 a cubic yard so $1260
Figured $300 for lumber and rebar.

Was definitely planing to put pins or rebar into old slab to keep them from shifting
Thanks to all who have given input, please continue to do so

I think your concrete numbers are a little off using the dimensions provided in the calcs above but not a huge budget buster.

Footing: 56.0x2.0x2.0 = 224 cf/27 = 8.3 cy, round up to minimum of 9 cy order
Slab: 20.0x20.0x0.5 = 200 cf/27 = 7.5 cy, round up to minimum of 8 cy order

17cy at $105 / cy = $1785

If pouring all at once, you might be able to save a yard but you better be damn sure the footing excavation and slab prep are dead nuts on - you don't want to be a half yard short at the end of the day.

I would also thicken the new slab edge that meets the existing foundation where you will be placing the overhead door.

What is the inspector going to require locally for rebar in the footing and reinforcement in the slab? $300 combined for steel and form lumber seems really light when you start adding dowels to the existing foundation, anchor bolts for the sills, form stakes & braces, and so on.

Overall, if doing it yourself I would double your estimate for the foundation plus an add for any tools you need to rent to place and finish the concrete.

 

[bczygan]

Here's how I think a general contractor will bid it, rough numbers for an urban area:

Looking at it after I posted, I left off the roof sheathing, which would add $200 or so more.

Updated my cost sheet for what I'd guess at for doing it yourself, except for the concrete:

Those are reasonable numbers, incl. sales tax.

 

[cgall]

You only need 2 walls, cut off the back wall and move it 20'

 

[bczygan]

Don't forget a couple of LVL's to header off the opening in the existing wall.

 

[ssdave]

In Houston, so no snow load, can probably header an 8 foot opening with a couple 2x10 or 2x12. Depends on whether it's gable end or load bearing also.

 

[shaveradam]

You only need 2 walls, cut off the back wall and move it 20'

ha! If only this worked in real life.