Starting a siding project,

55 year old house tri-split level  upper and mid  level  2x4 frame construction.

R11 in walls, poorly installed, many gaps.

Exterior sheathing is some fiber board, but after removing some siding the board apart, many holes.

So, looking to improve before siding goes up.

Contractor proposing R13, seal all penetrations while sheathing is off, install new plywood sheathing.

Thoughts?

I would like to do better than R13 and was thinking foam board on the outside of the studs for a thermal break and then sheathing.

I want to air seal as much as I can with siding off.

I probably can get away with 1/2 inch, not sure about 1 inch foam.

HVAC system is dual fuel, also replacing water heater with model that has sealed combustion through side wall.

Removing old through roof vent.

I want to get this right, I have lived here 30 years and have made many improvements to the envelope (attic, windows, duct sealing)

Northern VA.

Thanks.

At this point it came down to cost and time.

What is going in at this point is:

seal all wall/stud penetrations

R-15 insulation (3.5 inch)

R-5 Foam board taped and sealed (thermal break over studs) (1 inch)

Exterior sheathing

Rain shield

siding.

The crew is going after all the holes I could never get to from the attic and the inside.

Thermal camera and "hand over outlets" test show improvement.

I might be able to heat the house with my teenagers gaming computers....

I was thinking about that.  Contractor had better pricing on separate materials.

My window and door frames will accommodate the extra inch so not too bad.

Stripping the walls to the studs has allowed me to fix some issues as well.

When the house was built the outdoor light outlet boxes we not secured to the studs, old work boxes were used and screwed to the siding.

Fixed that and found to cable clamp in one box.   Ugh!