Hey Guys. My basement has no fire exit. I want to put an exit door in my basement wall so I can finish the basement into a rec room.

It is an external load bearing block wall and has a 18"x12" window at the top of the wall with timber framing above. Bsically, I want to enlarge the window to fit a 3'x7' door.

What's the best way to do this?

To do this properly you will need to jack the floor joists and perimeter plate to take the load of that section of the wall. A header needs to be installed, you can guess at the correct size or have an engineer spec it for you. Codes in your town may dictate this for you. Once the larger header is installed you can start cutting out the block below the header. I would try to line up on edghe of the new opening with the end of one row of blocks. This will help you install a 2x8 or 2x10 as a nailing surface for you door frame. I would use anchor bolts to secure the 2x8.

Thanks for the quick response. How would I temp support the perimeter plate and joists? Would an I beam perpendicular through the existing window opening work? Also, to install the header, do I take out an extra block or 2 on either side and set it in mortar or is it better to bolt it into the wall?

I beam would be great but put it perpendicular to the joists not the window, support with jacking column. Header goes inside the wall not bolted to it so knock out one block on each side of your nre door opening. Try to set the new header directly on the top of a block and mortar the seam above it.

Aaah. So, put the I beam against and parallel to the wall and jack it up tight against the joists to take the load. Then cut the door opening, remove 1 block either side, install the header in a bed of mortar at the correct height so when the I beam is removed, the joists would rest directly on the header?

You are right on the money. Lets picture the last phrase, "the joists would rest directly on the header?" The header actually will lay in direct contact with the block row below it. There will be a small space above the header and below the joists. Fill this will a shim board cut to fit.

Thank you so very much. I'm sure I'll have more questions once I get going with the rest of the project. You been a great help!

There are several of us here who can help. Come back anytime.