We need to rebuild our porch.
Taking it down removes the secure external door and exposes the non secure internal door.
That internal one is a narrow space, too narrow to fit an external door.

How do I keep the house secure during construction?
Is timber bolted over enough or do I brick it up?

Any other options?
Thanks.

2 pieces marine ply with timber spacer sandwiched in the middle. Coach bolts through all 3 pieces with the nuts on the inside. I’d do this top middle and bottom.

diawl2’s way is the standard method. Should be pretty safe. Depends if the building is in a rough part of town. Might also be worth checking with your insurers. We are having some work done and they have specified a few thing regarding security

I rescued from the street skip a steel door used when boarding up council houses, and then bolted as suggested above.