You definitely need an engineer to design the modification for you. The way they did it in the link, by basically bolting ledger boards on 3 sides, would only be appropriate if the 2 side walls are load bearing. If they just attached the ledgers to joists, they could get some serious sag down the road.

It can be as simple as the link, or some of the drywall might need to be removed to provide more support for the new floor. Costs vary so much regionally, that it's hard for anyone to give you an estimate. And even a local contractor wouldn't be able to estimate price unless he/she knew what structural changes needed to be made.

So I'd probably start by talking with a contractor or 2, as they could give you some sort of wild ballpark. If it's in the range of your budget, then hire a structural engineer to design it, and then bid the fully designed project to several contractors.

As for the window, if it's that low to the (new) floor, it should be replaced by one with tempered glass. That's code.

You guys are great. Thank you so much!!!

This may sound like a stupid question but where would I find an engineer? I've googled and I'm not seeing anything. I'm in Houston. Thanks

Google "structural engineer Houston" and you'll find some to call and chat with. Be prepared that some (many?) may not be interested in paying a home visit and designing something small scale. They may specialize in bigger stuff or commercial projects.

Another route would be to call a couple residential architects near you, explain what you're doing, and ask them for referrals to engineers. They may have one in-house, or they may have someone they send their engineering work to.

Thanks so much!

link below

Here is a link that might be useful: link

This post was edited by Renovator8 on Wed, Aug 7, 13 at 12:44

duplicate

This post was edited by Renovator8 on Wed, Aug 7, 13 at 13:04

I was asked to bid this same kind of project, and I was thinking because you will more than likely need a LVL beam, because the one I'm doing only has two existing walls, if you find a contractor they will order the LVL, and most companies that sell these structural wood beams have an onsite engineer in their cooperate office, (or a traveling one) to size it correctly. Depending on local building codes, I would call contractors first instead of paying for a design that should be included in the project price anyway. Either way is acceptable, but that's how I've done it in the past. But like the other person said most want bigger projects to make it worth their time.