Building a bedroom over a garage and attaching it to the house?

10 years ago

Hi All,

We live in an area in which the housing market is VERY tight and expensive. We have been looking for a new house for a while, and a "private sale" opportunity recently came up in our neighborhood. The house is a lovely and charming cape-cottage, but it is only 3 bedrooms and 1.5 baths. We would want to add a master bedroom and bath to the house if we buy it. The most obvious place to do this is above the 400 square feet 2 car garage. However, we think that the garage was originally detached and then attached by a small breezeway. It sits far back on the lot: almost starting where the back of the house ends aside from the breezeway that connects to the kitchen. We are trying to imagine how we could build a bedroom and bath up there (and would there be enough space?) and then attach it to the second floor where our kids would sleep.

An elderly woman is still living in the house, so we don't have easy access to it. However, we will need to make a quick decision about the house when the opportunity comes along. We welcome any tips about building above garages and attaching the space. Ballpark figures of how much this would cost? Is 400 square feet sufficient space for a master bedroom and bath? What are common ways to connect this sort of space to the rest of the house? Do people sometimes build a new garage further up and add on above that? (We are limited by strict set-back rules here.)

Thanks so much for any input!

Sara

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newenglandsara2
Original Author

10 years ago

Thanks so much for the input so far. Renovator8, the idea of rebuilding a new garage that is attached to the house is a great one. I wonder if code would allow such a thing. :-) Have you seen this happen successfully in the past? Live_Wire_Oak, are you saying that costs might be less if we start with a fresh garage that is right up against the house?

Again, I really appreciate the thoughts so far!

Sara

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Comments (8)

renovator8
10 years ago
The best approach would be to contact an architect. The first thing that needs to be done is to review restrictive local ordinances like zoning, drainage, wetlands, etc. and the building department file that will hopefully show the garage foundation.

I get asked to do this often and the most common problems are that a detached garage was often allowed to be closer to the property line than an attached one so when it gets attached to the house it is then "existing, non-conforming" and cannot have anything built on top of it unless the addition wall is set back farther far enough to comply.

It is also common for an old garage foundation/footing to be less deep and/or less wide than required by the current code. It is often necessary to dig down to expose the foundation.

since it is unlikely that you will get enough answers to these questions in time you might be forced to assume that the garage will need to be torn down and a new structure added to the house. It might be cheaper and would certainly be a better design.

This post was edited by Renovator8 on Fri, Nov 15, 13 at 5:15
live_wire_oak
10 years ago
See what new construction costs are in your location. Then double that (easily) for a difficult to integrate addition. If it includes plumbing, add even more.
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mag77
10 years ago
Do not make a quick decision! Don't buy the property unless you know exactly what the local building code department will allow you to do. You might not be able to build on top the garage, period. You might be able to build a room above the garage, but only if there's no plumbing. The garage might be illegal, but "grandfathered in" as long as you do nothing but repair and maintain it.
renovator8
10 years ago
The building code will allow an addition; it will be the zoning ordinance that will limit where it can be built. It is pointless to speculate about what it says. It should be online so find it and read it or hire an architect to do it.

If the setbacks are difficult to judge, perhaps the owner has a survey or a plot plan. Ask the real estate agent if you can see it. I suspect you will not be the first person to be interested in this information so the agent might already have it. Don't forget that the building department might have this information on file and its public information so just go to the counter and ask for the records for that address and make a copy of anything you find of interest.
jmc01
10 years ago
Is the foundation of the garage strong enough to support living space on top?
While your code might allow additions, will it allow an addition on something that basically has no foundation?
chibimimi
10 years ago
Does the layout upstairs allow you to add a connector to the new space without losing either a bedroom or a bath?
renovator8
10 years ago
To add a floor to an existing structure, the width of the footings and the depth below grade must meet the current building code requirements which is unlikely if the garage was built before 1975. However, if an architect, structural engineer or geotechnical engineer approves it, the building department will often accept it. There are also acceptable alternatives for protecting an existing shallow foundation.

Unfortunately only way to know the condition of a footing is to dig it up.

Where is the house located?