new insulation in old house... which product?
I am new to construction/remodeling and would like to ask a few questions about insulating our home. My wife and I recently purchased a 1500sf 1850s era farmhouse in Northern VA. The interior of the home is in pretty good conditionÃ¢ÂÂ¦ the walls are lathe and plaster, and have been recently redone, so I would like to leave them alone if I can. The outside needs work. The siding is in pretty bad shape and there is no insulation in the walls. We are installing an open-loop geothermal heat pump to replace the old oil furnace, and we need to address the siding and insulation. There is also an uninsulated crawl space that needs to be addressed as well. My plan is to rip off the old siding and replace with hardi-plank (to preserve some semblance of the historic look). But I am really not sure what to do for insulation. Money is a factor, but we certainly donÃ¢ÂÂt want to create problems for ourselves in the future.
1) Which insulation system should we install?
2) Can a regular fiberglass batt installation be done well and suffice?
3) Should we spend the extra money on full-foam, and if so, which product should we go with? Will foam damage the lathe and plaster on the inside?
4) Can we split the difference and do some sort of a hybrid system (flash and batt)? If so, which products should we use and where does the vapor barrier go? Keep in mind that I will have the exterior of the house exposed to do the work, not the interior. I keep reading differing arguments about this approach and the moisture problems it can create, so I need some clear guidance here.
Most of what I have read already relates to new construction with products being applied to the inside of plywood sheathing, and working in towards the drywallÃ¢ÂÂ¦ however, our situation is reversed since we are taking all of the exterior siding off and re-insulating from there.
Thanks in advance for the help!