ECN Forum Forums General Topics of the Trade General Discussion Area Determining Square Feet

Hi,
I am wondering what the best method is for calculating the total square feet in a single family dwelling? This is a two story log home that is not square but irregular.

Do vaulted ceilings, stairwells and storage rooms with electric count?

I think Fannie Mae set the standard by using ANSI 2003.

The house was bid on 4000 sq ft and now I find out it is actually 5400 sq. ft.

How can I be sure that what I am being told is correct?

Happy New Year!

Thanks for any replies.

Greg


[This message has been edited by mustangelectric (edited 01-03-2005).]

well the simpliest and most time consuming idea is to measure every room and add that up if you allready bid this at 4000 and it is really 5400 i would not chance it i would just measure every room
who knows it could be over 6500 sqft

Hello Greg, I don't quite understand your question. Is there something beyond 220.3(A) that needs to be taken into consideration?

The vaulted ceiling/s would not be an issue, the stairwells and storage rooms (used spaces)would be part of the floor area computation.

Roger

Hi,
The code says drop the garage but I bid based on TOTAL SQUARE FOOTAGE. Why the garage would be excluded is not clear but I have never seen but one garage that did not have lights, recepts etc. As a matter of fact most garages nowadays serve as the mechanical room for equipment like electrical, HVAC and garage door openers.

I read up on ANSI and they include the stairwell and vaulted cielings above 7 foot.

I measured from a drawing the exterior walls because even dead wall space is counted as well as any room that has an outlet.

The shape of the house is not totally square so I broke it up inot sctions that I could figure.

I know that realtors and banks have different methods.

I realized that something was not right by the amount of wire that I already used.

The house had a 200A service already installed.

It is ALL electric with dual 60A heating elements, 40A AC, electric HW and electric range and 240 vac micro, spa, and..there are already over 25 recessed cans and over 20 regular lighting outlets. Another concern is that the service is too small.

3 watts per square foot on lighting alone is 60A.

-regards

Greg

I think a 200 Amp service for this size home with all electric is too small. My rough calculations come to around 215 Amps and you would be well served to upgrade to a 400 Amp Service.

Hi,
There was a 200A CSED mounted on the pole when I showed up.

It is an underground service that is 125 feet from the house.

I installed a 200A main panel and a 100A sub panel which are almost full.

There is Electric Heat two 60A disconnects, Electric Range 50A, Electric HW 30A, 240V Micro 20A, Dryer 30A, AC 40A, Dishwash 20A ,Disp,ref and tons of lighting and 5 ceiling fans at 60A.

What do I do now? There is no way they will pay to upgrade now.

Am I responsible for this mistake?

-regards

Greg

[This message has been edited by mustangelectric (edited 01-03-2005).]

Greg, the smaller load of heat or A/C will be cancelled, the range will only be 8 kw, there is a better than likely chance there is not a problem.

Can you post the actual fixed loads so we can have a calculation party?

Roger

Boy am I glad I'm not you! But seriously, here's my unsolicited opinion:
I have 4 rules that there are no exceptions to.
1)Never ever ever ever ever bid a custom home by the square foot.

2)Never wire a new house where someone else has installed the service entrance without a detailed written agreement full of disclaimers pertaining to the service size, location, and equipment.

3)Never agree to finish wiring a house someone else started without another long, detailed written agreement full of disclaimers.

4) Never accept a job on someone else's service calculations and electrical lay-out. Not even the architect's.

I don't know what the answer here is for you in this situation. If you just finish the job as is it will probably be your name that is mentioned every time their is a problem and there could be many if the service is inadequate. You could make things right out of your own pocket and count it as an expensive education. It may sting but it will be cheaper in the long run than a bad rep. A lot depends on who you are working for. Is it the homeowner or a GC? I would suggest that you run, don't walk to who ever that may be and do some explaining and negotiating. Good luck.

I get 207 amps figuring 5400 sq.ft. and what you listed and that's with the minimum 2 SA branch circuits.

Hi,
Thanks for the replies. The HO says the bank says the actual square footage is 4800 but I am guessing this is Heated living space only. The garage is not counted in the NEC so I will have to find out if that is in there or not.

80% load is all you are allowed right?

I will have to measure the house myself to be satisfied.

Fred,
This was a brand new house. There was a NEW 200A service on the pole that was basically used for temp power. The HO had this installed before we ever met. I bid all homes by the sq ft for basic wiring only. Anything above what is required is extra and I give a list of what those cost before hand.

I see no need for special provisions on a service installed on the pole. I installed a service lateral and a 200A main panel at the house. I am not responsible for the panel on the pole or the size of it.

There was no previous electrical work done on the house just at the pole.

There were no plans, no calculations provided everything was AS-BUILT. This is spelled out in my proposal.

The only problem I see is that if the actual square footage is 5400 then the loads will more than likely exceed what is allowed. Even if there is 4800 sq ft. I would still rather see a larger service.

Had I been asked I would have recommended a larger service based on just common sense alone. From a clean slate with no plans I could easily wire a 5400 square foot home with a 200A service. That doesnt leave much for future expansion though.

The worst case scenario here is that the service will need to be bumped up to 400A but I do not see where it is my responsibility.

Should I have told the HO that the new 200A CSED they had installed has to be replaced by a 400A service? I would have anyway had I known. Why would that fall into my scope of work?

I will post the actual nameplate ratings and the actual sqf as soon as I can get a 100 foot tape out there.

Do I really need to go out and measure each and every house?

You wont get any work around here if you do not bid by the sqf.

You may get one or two and I do but the bulk of my clients are shopping.

I used to bid by the opening then got griped at for that! How the heck are you supposed to bid a house?

I can almost guess how much material it will take and get pretty close to how many hours it will take and how many trips I will have to make etc but I have yet to come up with a solid method.

A takeoff is fine when you have a set of plans. But you may not win many bids using that method.

I am a sole proprietor.

Thanks for the replies..and suggestions..

-regards

Greg

[This message has been edited by mustangelectric (edited 01-03-2005).]

[This message has been edited by mustangelectric (edited 01-03-2005).]