Home>Discussions>EXTERIORS>Adding Transom - Carry Load Question
4 posts / 0 new
Last post
Adding Transom - Carry Load Question

Question, I am replacing an existing front door with two side lights. The door is 36" x 80" with two side lights at 12". We also wanted to put in a transom that is not existing. So the new rough opening is 64 x 96 for the door. Currently above the door I have a 2x4, 2x10 (header), and 2 2x4 for the first floor, then the second floor starts with a 2x10. The interior second floor 2x10 is continual across 79”, not sure about the exterior 2x10.

To install the new door, I would need to remove the 2x4, 2x10 header and the 2 2x4s. But my concern is to carry the load of the house. I am ok of installing additional 2x4s on the sides, but was trying to figure out how to carry the load. My thoughts is to use a L steel beam that is turned upwards over the 79” of the foyer, with 3 2x4’s on both side to carry the load. The steel beam would be bolted into the 2x10 on the second floor.

I am calling the zoning board on Tuesday to determine what they think. But was also thinking of what others think to get the best way to carry this load.

Your thoughts would be grateful.

Thanks David L Gorman

Re: Adding Transom - Carry Load Question

I think you need to open a little more of your wall. It may be posible the the upper 2X10 ,if it is a 2X10, may be a ledger board for a porch roof. If it is I think you'll need a little more suport to replace the header. Possibly a ¼" 10"X79" piece of steel plate srewed and glued to it.

Re: Adding Transom - Carry Load Question

Jack, thanks for the insight. The upper doubled 2x10's are in good shape and they are the 2x10s that hold the second floor, no porch, looking at that as my next project. Yeah my thoughts is to use a steel beam that spans the foyer upper 2x10s with a L beam. And use three jack studs to carry the load down to the sub floor.

Thanks David

Re: Adding Transom - Carry Load Question

I suspect there is actually a doubled 2x10 for the header and with the 2x4 on the bottom combined the the 2x4 from the top plate this is basically an I beam header. This is a very strong structural member designed to carry a lot of point load not only for the downward force but also from horizontal bend. This was likely sized according to stress loads that are at that door and is not your typical 2 2x8 you might find.

Since you will reducing the depth buy about 16 inches of the supporting member it's possible you may be going to a steel I beam with additional vertical members as well it will depend on the side forces as well.

You really should have a professional calculate what is appropriate for that support since that is one serious header.

It's going to be an expensive transom that's not very big.


Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.