Hi - I recently purchased a 1930s home that has an addition that was put on the back of the house in the early 2000s. The addition has a curtain foundation with concrete block piers but has lumber spanning between the piers (not brick or concrete block that seems typical). Unfortunately, a good portion of the curtain foundation is below grade by 6-12 inches and more in some areas. The builders poured rumble stone in the crawl and around the outside of the foundation and they used some sort of metal flashing to "protect" the wood spanning between the block piers. There is ductwork, plumbing etc that goes into the crawlspace from the main part of the house. There is mold and the builder put insulation in the floor joist that has to be remediated. Mold is likely from high humidty and ductwork that is poorly insulated that is condensing.
I have been told by a reputable encapsulation company that because there is not a continuous block or brick wall and there is wood spanning between the piers that they cannot fully encapsulate this space. I live down south so have a very high humidity environment. My living room and master are above this space.
I would love to know what is the best approach for insulating the flooring for this particular problem? One option I have heard is to use foam board insulation between the floor joist held in place by spray foam and then to cover the joist with pressure-treated plywood. We would seal up the foundation wall between the two crawl spaces and around ducts etc. We would add vent wells so all of the vents are open and then fans to encourage airflow.
If we take this approach would it still be a good idea to have poly covering the exposed dirt in the crawl or not a factor because we have "encapsulated" below the subfloor?
What are risk with having ductwork and plumbing running through a vented space?
Alternatively, one option is to assume that the metal flashing provides a sufficient barrier around the crawl space we seal all the vents and we cover the exposed earth as best we can by pinning the vinyl down on the edges and then have a dehumidifier running in this space. Is this likely to result in sky-high power bill with the dehumidifier having to constantly run or taking steps as outlined will likely drop the humidity a good bit and a commercial-grade unit could handle it pretty easily?
Thanks for the advice!
I have been told by a reputable encapsulation company that because there is not a continuous block or brick wall and there is wood spanning between the piers that they cannot fully encapsulate this space. I live down south so have a very high humidity environment. My living room and master are above this space.
I would love to know what is the best approach for insulating the flooring for this particular problem? One option I have heard is to use foam board insulation between the floor joist held in place by spray foam and then to cover the joist with pressure-treated plywood. We would seal up the foundation wall between the two crawl spaces and around ducts etc. We would add vent wells so all of the vents are open and then fans to encourage airflow.
If we take this approach would it still be a good idea to have poly covering the exposed dirt in the crawl or not a factor because we have "encapsulated" below the subfloor?
What are risk with having ductwork and plumbing running through a vented space?
Alternatively, one option is to assume that the metal flashing provides a sufficient barrier around the crawl space we seal all the vents and we cover the exposed earth as best we can by pinning the vinyl down on the edges and then have a dehumidifier running in this space. Is this likely to result in sky-high power bill with the dehumidifier having to constantly run or taking steps as outlined will likely drop the humidity a good bit and a commercial-grade unit could handle it pretty easily?
Thanks for the advice!