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October 30, 2007
Does it cost more to add a top floor or an extension?
anyone know what the difference in price would be between building a 16x12 foot extension on one floor (and maybe a 9x12 extension on top of it) vs. building a 4th floor 16.67x36 on a three story brownstone? FAR allows for either/both...
Comments
First, check the height restrictions for you street. Even if you have the FAR, you may be restricted as to height.
If you can build higher, the cost may be more for add ons like windows, stairs and decking. Otherwise, in general, the cost is determined per square foot. The average being around $300 no matter if you build up or accross (it varies greatly, and depends on the quality of the materials and workmanship).
Posted by: guest at October 30, 2007 12:52 PM
Thanks. I read somewhere that if you build a floor you also have to fortify the rest of the building to make sure it can carry the weight, and since I casually knocked out the wall btw hallway and front parlor on parlor floor, without adding an extra carrier beam, house probably wouldn't be able to carry another floor!
Posted by: gws at October 30, 2007 2:51 PM
Not necessarily, when I looked into it, one suggestion was to install beams accross the width of the building resting on the exterior walls. This would not really cost that much to do.
Posted by: guest at October 31, 2007 10:09 AM
Beams can rest on the exterior walls if the walls can bear the weight. It all depends on your walls. An engineer can definitely tell you. Who knows, your buildings walls might be reaching its limit at 3 stories. Regarding your knocked out wall, that was -probably- not even a load-bearing wall, as your beams would be running the width of your house, which I will assume is about 17' and all loads on that floor should be transfered to the exterior walls.
Posted by: sxm at October 31, 2007 12:20 PM
i know when building up you can save on heating and electricity cost bc you are just bringing them up from the floor below...as opposed to new in an extension
Posted by: guest at November 1, 2007 8:28 AM
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