Mold is becoming the biggest health concern in the eastern US. Does building with Hebel block minimize or eliminate mold growth?
I am looking for a very energy efficient way to build a house and to avoid all mold issues inherent with plastic wrapped houses that can’t breathe. Living with mold greatly increases symptoms of Lyme disease.
Got any suggestions?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
Margery,
I imagine that health professionals might disagree on your conclusion the "mold is becoming the biggest health concern in the U.S."
If you want to avoid indoor mold -- it's pretty hard to avoid outdoor mold, because mold is everywhere -- you should keep your indoor relative humidity low (that means you should never run a humidifier, and you should operate your bathroom exhaust fans when necessary during the winter) and pay attention to basic housekeeping. A clean house is usually not a moldy house.
Hebel block is a brand name of blocks made of autoclaved aerated concrete. A house made of Hebel blocks can certainly be moldy, and a house made with a different type of wall can be mold-free. Factors other than wall construction are far more important when it comes to keeping your house mold-free.
Option B, don't wrap the house in plastic! Houses don't need to breathe. People do. Build it as tight as you can afford with mechanical ventilation and make sure that it has a chance to dry out of it gets wet and it'll be fine.
Thanks for your answers. My experience is with black moldy framing that was soggy when uncovered due to a hidden leak from the roof that ran down the inside of the wall and rotted out the floor and eventually released the tiles from the bathroom wall. The resulting mold made both of us sick and as we work to find any remaining mold in other walls,over the past few years, we find that my husband still is much improved by sleeping outside every night in a hosed down tree house . We thought if we could find a more suitable building material that would not get as moldy even if there were hidden water damage. Wood feeds mold, we were hoping concrete did not.
and yes, ok behind obesity, insulin resistance,heart disease, cancer memory loss, then mold comes along, and it exacerbates other issues especially autoimmune problems.
Margery, my sympathy for your situation. A moldy home can be extremely debilitating and not easy to fix. If you are planning to build a new home and wish to avoid these problems in the future I'd suggest you abandon your quest for mold-resistant materials - there really are none. While it's true that masonry is less likely to suffer structural damage from wet conditions, the mold from which you are suffering will grow on virtually any constantly damp material. Being sponge-like and very absorbent Hebel is as bad as any. Focus instead on preventing water saturation of those materials, whatever they are, in the first place.
Clearly one of the most important things you can do is insist on a properly designed roof with the minimum long-term potential for leaks, hidden or otherwise. Simple designs are best with a decent slope and good overhangs. Here's a link to Martin's excellent commentary on roof design:
https://www.greenbuildingadvisor.com/blogs/dept/musings/martin-s-ten-rules-roof-design
You also need to employ an excellent plumber to make sure that your interior pipes stay leak-free over the long haul, and make sure that condensation will never be a problem by installing proper insulation, ventilation and air-sealing as appropriate to your climate and use patterns.
There's a wealth of information on GBA to help you with this, but your most important first step is to team up with local professionals in design and construction who not only share your goals but have done this before and have deep experience of local conditions.