Thank you for the compliment. Iíd like to think Iíve been around the block a time or two when it comes to residential remodeling and construction, but in truth one cannot live long enough to experience everything.
No, I do not feel you have to rip up everything in your house when the problem is under it, but a conversation earlier today with a friend of mine reminded me that, although I have had experience with your problem in my neck of the woods, some of my suggestions may not translate to your region. I have a couple of questions, if you donít mind:
∑ What area of the country are you in.? ∑ How old is your house? ∑ Is it one story or two? ∑ Did you find any vents around the perimeter of the foundation? If so, were they obstruction-free, and can they be opened? By chance, do you have any basement at all, and if so, are there any windows? ∑ Besides floor joists, you must have a center beam. Is it made of triple 2xís, laminated beam, or steel? ∑ Is whatís under your house dirt or sand? If sand, dig down a little to see if there is a buried plastic (or other material ) covering? ∑ What is the condition of your sill plates? Those are the pieces of wood laying flat along the top of the perimeter foundation walls, and the rim and floor joists rest on top of them. If your house is really old, you may not have any. If you have them, and they are rotting as well, you may have more work. When they go, your house may start to settle crooked, and walls begin to crack and floors to buckle. Replacement usually involves jacking the house up.
Iím in the Mid-Atlantic area, about 50 miles North of Philadelphia. Most houses in the area have full basements or basement/crawlspace combinations, and more recently, monolithic foundations, which in laymanís terms is a concrete slab. However, I have worked with full crawlspaces at the New Jersey Shore area. One of these projects needed similar work to yours.
Iíll try to justify my questions. If your house is older than 20 years, the insulation under the house was probably added later. Regardless, that insulation may be the true cause of the poor condition of your floor joists, and the smell in your house, since it will absorb airborne moisture very quickly, and pass it on to the adjoining joists, and even the subfloor, so consider inspecting the subfloor as well. A mildew smell in your house tends to tell me that moisture is being driven into your floors faster than can dissipate under there. Since you are going to replace many joists, you will need to pull at least some of the insulation down. You might consider pulling it all down, and depending on where you live, not replacing it. It might be doing more damage than good. Builders around here are divided as to its value, since heat rises, and most heat loss is in the attic, windows, and upper walls. Several friends of ours have new houses without it, our current house is 8 years-old and has it.
If you answer my questions, Iíll try to answer your additional questions and make some suggestions based on what I know. One stop-gap measure that might work is to place a small dehumidifier in the wettest part of your crawlspace. Make sure it is not a fire or electrical hazard, and drains outside or can be drained quickly. I have done nothing but put dehumidifiers in basements when there was a strong musty smell, and within a week or so the smell was gone.
As additional advise, you can get ideas via estimates from qualified professionals in your area. Consider a home inspector if you have not already had one. Even your municipality can be a really big and unbiased source for all your home questions.