cost of an addition, rough estimate

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Old 06-17-02, 12:35 PM
Mosey
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cost of an addition, rough estimate

Iím planning to build a 16 foot x 24 foot addition (384 square feet), which will be 2 bedrooms. Itís a pretty simple addition, extending the length of my ranch house another 16 feet. There is no basement, just crawl space. Iím planning to do it myself. Iíve heard that a good rule of thumb to have a contractor in my area do everything including wiring and extending the ductwork and finishing the inside is $75 to $100 per square foot, or $29k to $38k. So based on that, without having to go through and total up the cost of the materials, how can I come up with a rough estimate of how much the materials will cost of I do it myself?
 
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Old 06-17-02, 01:41 PM
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cost of an addition, rough estimate

Mosey,

You're asking a question that many ask and without having some more specifics, anyone could give a price and it might seem good but will it be somewhat close to what you think it will cost? Not knowing if this is 2x4 walls or 2x6, stick built roof or trusses, dimensional lumber for floor joists or TJI's, how many windows and what type, any ceilings going to be vaulted, what is going to be used for siding? Any trees have to be removed, powermast relocation,etc.? Is there easy accessibility to work site? What has to be demo'd, renovated to gain access to this addition, do you have a hip or gable style roof?

Some say figure at least 50% for cost of materials others say a little less versus the estimated cost per square foot finished. I would like to stress that when I use a ballpark estimate such as $100 per square foot, there are other issues that must be addressed. Not only do the above items effect the cost but finish flooring, any electrical upgrades and is there a need to look at the HVAC system to accommodate the additional space.

I always figure adding 20% more to the $100 sf rule since many things effect the cost. For 2 bedrooms this is sure alot of added square footage? I am assuming that something else is going on here besides bedrooms.

I would suggest getting some drawings done and taking them to your local yard for a material take off. If you are serious about doing this addition, don't guess what it is going to cost for materials. Hire a good building designer or architect and get plans done and establish a budget based upon what you are wanting and what is required by code, you're going to need plans anyway for a building permit. Once you have established costs, you may want to reconsider on doing this all yourself.

Got any questions just call, hope this helps!
 
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Old 06-17-02, 02:04 PM
Mosey
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Doug,

Thanks for the feedback. This addition is about as simple as they can get. No trees or anything to worry about and Iím on 6 acres so thereís plenty of room. I have the equipment available (neighbor) to dig out the crawl space, and Iíll pour the footings myself. Then, itís just the floor joists, and 2x6 walls and the roof, using pre-made standard trusses, to frame it all in. Single story with a gabled roof and plain shingles, T-11 siding (since itís on the back of the house). One window in each room. The heating/AC system is big enough to handle it, so all I need to do is run the ducts into the addition. No plumbing, and electrical is just plugs and lights. The room sizes will end up at around 11 feet by 13 feet, not counting the closets. It may seem big for a kids bedroom, but Iíve seen bigger and want the kids to have plenty of room for a computer desk, etc when they get older. If the cost ends up being too high once I figure it out exactly, I can go smaller.
 
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Old 06-19-02, 07:22 PM
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You materials will probably cost you about $15,000 to $18,000.
It is all the little things that add up that you do not think about.
For example, the correct way to attach it to your house. You cannot just extend the roof. It will look bad, and probably leak.
You roof will be one of the largest single costs. Trusses, 5/8" sheeting, felt shingles, nails, gutter, metal, and the list goes on.
For you this is a big job, for a contractor it is a little job. You can do what you like, but, make sure your Home Owners insurance will allow you to do it yourself. In many states they do not. I would have the contractor, frame it in, put on the roof and siding and seal it up. Then you could finish the inside. Just a thought.
 
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Old 06-20-02, 12:56 PM
Mosey
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"I would have the contractor, frame it in, put on the roof and siding and seal it up. Then you could finish the inside. "

I'll look into that idea. Thanks for the info! I don't really have the time in the summer, but need a winter project.
 
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Old 06-22-02, 08:10 AM
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Finishing off the inside will make a great winter project.
 
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Old 06-22-02, 09:37 PM
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Cost of addition

Costs of material and labor tend to vary depending on what area of the country. Make sure you check with the local authorities regarding building codes, permits, and inspections.

http://doityourself.com/enjoyinghome...outpermits.htm
 
 

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