Windows or Siding First? Need Advice
We are getting ready to start a large, multi-year remodel of a mid-century designed house built in 1949 and need advice on if we should replace windows before or after installing insulation and new Hardie Panel siding on the exterior of the house.
The exterior walls are all one foot thick concrete blocks with the voids filled with concrete. All of the walls are solid with no cracking or settling. There is no additional surface either inside or outside the house on the walls. (The cement block you see on the inside of the house, is the internal surface of the same cement block you see on the outside of the house.)
The windows are all original to the house construction in 1949 and need to be replaced. If it helps with advice or opinions, we are looking at going with the Marvin Ultimate clad line of windows and going with full-frame (new construction) and not just window replacement.
We live in the central Michigan area where the winters can be very cold; especially last winter! And, the summers can be warm and humid.
We are planning on installing either two or four inches of ISO to the external walls and then siding with four-foot by eight-foot Hardie Panel fiber cement panel siding to maintain the modern look of the exterior. The plan is that the ISO would increase the relatively low insulating value of the essentially solid concrete walls and move the thermal mass to the interior to help regulate swings in the inside air temperatures. This plan will increase the thickness of the exterior walls and will need to somehow be accounted for with the framing or trimming of the new windows.
We have talked with several contractors and are getting conflicting advice as to whether we should replace the windows first then insulate and side, or if we should work on the insulation and siding and then replace the windows.
If we replace the windows first, our worry is that the any work to extend the exterior of the trimming of the new windows will turn them into some sort of Frankensteined look that will not match the modern look of the house. But some of the contractors have stated that we need to start with the windows and not to worry about the increased thickness of the walls after the ISO and Hardie Panel installation.
If we do the siding first, we are concerned about how the new insulation and siding may have to be damaged when the windows are replaced.
Should we replace windows first or work on the insulation and siding first and follow-up with the new windows afterwards? We are self-funding the remodel work and can afford to do one or the other this year, but not both.