Anyone With Experience Adding Shed Dormers?

5 Replies

I just bought a house in a neighborhood where most of the houses were built in the late 1920's to early 1930's.  We've gotten all of the mechanicals up and running (finally - took nearly 3 weeks just to get an electric meter installed) and are now moving to the roof.  Most of the neighborhood has had shed dormers added to increase the usable upstairs space and I'm looking to do that to this house too in order to add a bedroom that an average adult can use (the upstairs bedroom is chopped up into two tiny rooms that a twin bed cannot even fit into and the ceiling heights are not to code.)  Problem is, I've been chasing contractors for two months for estimates.  I finally got three to come out and can't get responses from these people.  So, I called another and got him out.  He gave me an estimate of $25k, without permits or architect fees, to replace the roof (it's a 24x26 box with a 12/12) and do the exterior of an appx. 12 X 20 shed dormer with two low end windows and vinyl siding (no sheet rock/electric, etc. - I can do all of this myself.)  This sounds really high to me for an added appx. 250 SF of unfinished space.  Maybe NJ really is double the national average on cost.  Anyone else had any luck with dormers or can recommend someone you've worked with?  Is it worth the money for the additional space?  How much do you pay on avg in NJ for a project like this?

Any advice/input is much appreciated.  Thanks in advance!

That actually sounds about right.  Also, when the house was originally built, if it wasn't engineered for the additional load the floor will be carrying below, you will need to get a structural engineer. You may be able to get a residential designer to work with a structural engineer rather than a licensed architect, and save a little, it depends on the laws of your state. But engineering will be the most complex part of the job. We were going to put shed dormers on a remodel, but with the time involved, costs, etc., it didn't make sense. However; if you're living in the house yourself, or if you're doing as a remodel and have the time, it does add a lot to the house. 

Here's a link I found on costs, and various types of dormers

I second @Karen Margrave . In tri-state area, that sounds about right. $16-20k range is what I'd say but he's probably a little on high side since it seems most contractors these days in the area are very busy therefore they can choose what they take on. 

Karen is also correct in that you will need to make sure the framing for the attic space is adequate for a habitable space. Also you may need a new stair if one is not already present for access. 

Disclaimer: I am an architect, but I am not YOUR architect. I am not giving professional advice only general information. Contact a local architect/engineer for a detailed consultation specific to your project/locale.    

Thanks for the input!  Very helpful!  Yeah, I was thinking closer to the $20k mark.  We will be moving the stairs, but I'm lucky that my father builds stairs for a living.  Do you all have anyone you work with that is responsive?  I'm having a hard time getting people to follow through with bids.

All great responses. I've worked in the custom home business and I would second that the engineering will be the biggest hurdle to jump. Often, though older houses are built with actual dimensional lumber, they aren't designed to carry loads like houses today. It's likely the ceiling is built with actual 2x4's, which wouldn't be enough to carry much traffic. Designing a new floor and roof will certainly eat a big chunk of the budget. All in all, I think the $20K is probably about right because you'd likely need to beef up the floor along with the roof, as long as the foundation can also hold the extra weight.

Hope that helps! Good luck!

I don't know what part of the world you are in but you will more than likely need to add framing to be in accoradance with today's minimum codes. If it was just attic space before and you want to make it a livable space then 2x4's will not fly. Also, he will have to look at the entire structure including the foundations. I've seen some scary stuff built back in the early 1900's and as soon an engineer puts his name on it he is responsible for everything.