Cost for a 35 X 25 above garage addition

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Posted by: from Pickering
12/13/2016 at 4:05:01 PM


I am interested in placing an above garage addition that is around the same size as the garage below. The area of the addition would be approximately 35 x 25 or around 900 sq. ft. The room would be for a new master bedroom, ensuite bathroom and walk in closet/storage room.

My two main questions are:

1. What is the approximate cost for the construction component including electrical, hvac, etc.

2. Would a new roof have to be placed or could we use the existing roof?


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Date/Time12/13/2016 at 10:04:23 PM

Hi John,

You would be looking at around $150-$180 a sq/ft depending on finishes. Which would put you in Between $135k-$170k all in including permits, plans.

For the roof portion it will have to be new to meet today's requirements for structural.


Scott Lawson

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Date/Time12/13/2016 at 11:06:27 PM

Adding a living space up is cheaper in comparison with building aside if no foundation reinforcement work will be involved. Normally prices start from $200 per square foot and might go up to $500 / ft2.

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John in Pickering
Date/Time12/13/2016 at 11:40:21 PM

How would we know if foundation work would be necessary? Also would the ceiling of the garage need to be reinforced at all?

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Date/Time12/14/2016 at 6:57:37 AM

First thing you must do is contact a local structural engineering firm to confirm you have enough Foundation & footing strength to support the build and if you have forced air heat now, is your existing furnace going to support the extra run over your garage. Your garage ceiling may have to be built up or changed , rules about rooms over a garage are very strict ,a good seal and good independent ventilation .Roof would have to change to meet up with codes. Get plans made up in advance and seek out at least three contractors (check "TrustPros"). Your probably looking at between 160K to 200K for the build and your finishes.

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Date/Time12/14/2016 at 11:39:01 AM

Typically alot of garages are built on slab on grade however some will have grade beam and piles and you will need to know this and how many piles and placement before you can go up. A safe number would be 150k not including demolition of the old structure. It is typical that your old garage is not built to hold a second storey and would need too much bracing to warrant keeping.Depending on the roof trusses you may be able to keep it but not likely worth it in the long run.

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Date/Time12/18/2016 at 10:40:18 PM

The drywall package including material, labor and disposal would be $2500-3000.

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