There’s a new housing development that I pass by each morning on the way to work. Typically, its pretty dry here in Southern California, but this morning it was raining. I know mold is an insidious problem that is really hard to get rid of, flood-damaged homes are sometimes unsalvageable. How do newer houses prevent that? All the wood and foundations are all out in the open and exposed to the elements
For somewhere like Seattle, where it rains a lot of the time, do they cover up the houses somehow to prevent mold from forming in a new building? How do they do it with so many rainy days?
In places that snow for many months out of the year, do people simply not build any new buildings during winter and spring? I’ve seen skyscrapers under constructions in places like NY, I’ve never really seen pictures of them in the snow though I’m guessing that happens. Are crews working in the snow too? Some buildings take over a year to build, are those plots just left empty when there’s a storm?
I’m not in the construction trade but I worked on a few Habitats for Humanity builds. People continue to build houses even during seasons when it might rain. If they didn’t no new houses would be built in much of the country. I don’t think it’s that big an issue because a house with no windows and siding has a lot of airflow. The house will dry out before fungus takes hold. The stuff that’s exposed to the rain, like timber and roofing materials, can handle the weather.
At some point, the walls are up, the windows and doors are in, the roof is on. At this point, the people who led my builds referred to the house as “dried in.” Then, weather sensitive materials like rugs, drywall and electrical components could be installed in the building. If a built house floods, all this stuff gets destroyed. If a built house has so much moisture that it promotes mold growth, it probably also has enough insulation to restrict airflow to allow the drying to kill the mold.
Wood can get wet and then dry out again with no problem. That’s why wooden decks usually don’t get moldy. It’s when something is enclosed and protected from the sun and wind that moisture can persist and mold can grow (the sun will also kill mold as well as dry things out). Also, there are lots of materials in a house - drywall and insulation - that won’t dry out like wood will. Those don’t go in until after the roof is over the house and the outer sheathing is up.
This. Drywall and flooring are the things that trap moisture, and they are among the last items to be installed in an under-construction house. Once the exterior siding and roof are in place, there’s plenty of time for the subfloor and stud gaps to dry out while workers install plumbing and electrical.
It is an issue. In many cases the house has to be “dried in” before it can be insured or in some cases financed by a mortgage. Before that it is a different class of risk, and often the builder fronts the money to get it to that point.
My sister’s house had a foot of snow drifting inside while it was being built. 20+ years later there have been no issues.
I watched them build a super-expensive house recently. They made no effort to protect it from the elements until it was time to put the roof on. Then they brought in a huge team on a dry day and tried to get the roof on in only a few hours, during which time other teams hastily put in the windows and doors.
Tired and Cranky is spot on correct in his post #2 above. The water doesn’t really soak into the wood framing members, so any break in the rain and it will dry out enough to inhibit mold growth. Once we’re “dried in” things will get dry rather quickly. Anything that can’t handle the rain has to wait to be installed after the dry in; like electrical and drywall. Drywall finishers very typically bring in big heaters and big fans to dry the interior out quickly and effectively.
One exception to this rule is the underfloor insulation. This is installed before the flooring deck is nailed down and can be ruined if it’s exposed to long rain events. Usually the rest of the framing can be thrown up quick enough and the roofing materials laid down to get things dried in … but I’ve heard tales of carpenters having to replace this insulation and boy that’s a dirty dirty job.
Mold requires water to grow, so if you are finding mold in your home, then the water is getting in somehow … perhaps a leaking roof, leaking plumbing or inadequate venting (typically in your bathroom) … the first step in solving a mold problem is solve the water leak problem first.
Built many houses in Alberta from ground breaking onward, some of them pretty big (and hence a longer time before its sealed up). Never heard the term ‘dried in’ or of dehumidifiers being used. In flood restoration we will run an extractor to get humidity levels down after removal of water damaged materials, but this isn’t necessary during initial construction phase.
Its certainly best if there is a few weeks between shingles going on and drywall up to give everything a chance to dry out. The moisture content of the framing lumber is usually still a little high when it comes from the yard, so even if the house does not get rained on during framing the lumber still needs some drying. During the back framing stage after the mechanical is in there will be some studs that have bowed and twisted during drying and its a good time to replace them.
One thing that can take a hit from rain and snow during framing is OSB subfloor. Water will puddle on the subfloor and sit for a long time. Most T&G subfloor products now have notches in the tongue and groove to allow water to drain off more easily, but sometimes this isnt enough. A good site manager will make sure they get squeegeed off and even drill holes to let water drain. The edges of the panels tend to swell if it is wet for too long and may need to be sanded down before finish flooring is installed.
I do occasionally see some builders install the newer roofing membranes (that are replacing tar paper) during framing, and this will keep most of the water out.
AdvanTech[sup]®[/sup] (and similar products - but are there any?) is an alternative to OSB that is water resistant. Some builders have found that the use of AdvanTech has actually saved them money, since they don’t have to worry about installing a roof ASAP after installing the subfloor.
I’ve passed a small, partially built (no windows, but roofed) house every day for the past six or so years.
I finally heard the tale. A guy and his gf had enough cash to build a house. He used all his savings to purchase the land, have some excavation done, pay various fees, and purchase concrete blocks and lumber. He and a few relatives got busy and built it to the point it’s at now.
At that point, the woman’s money was going to pay for the remaining things (windows, shingles, siding, etc). But she left him.
For the first two years the guy kept the window holes covered with dropcloths, but eventually he stopped doing even that. A few years after that he tried to sell, but at that point the house was a negative, needing to be torn down. I pass it every day.
It’s really not an issue for the framing to be rained upon because it isn’t the first time the lumber has been wet. Prior to delivery to the site it was probably stored in an open lumber yard subject to the elements. Wood’s enemy is repeated wetting and drying over an extended period (usually years) that will result in decay.
We get a little rain from time to time.