You might think your house only becomes watertight when the siding, brick or stone is completely installed. Actually, sidings of any kind, including masonry and stucco, are not as watertight as you might imagine. They are not the last line of defense against water.

I refer to siding, brick, stone, stucco, and other sidings as the “weatherproofing” of the house. These materials keep the bulk of the wind and water out, but even perfectly installed siding material will still let in small, but significant, amounts of moisture. There is no effective way to stop this and it does not indicate the house is poorly built.

Do you remember the old black tar paper that used to be installed around a house before the siding was installed? That layer is the actual barrier against water infiltration. It is the true waterproofing of a house. These days, tar paper has been replaced with several high-tech House Wraps, like Tyvek and Typar by DuPont, Weathermate by Dow, and PinkWrap by Owens Corning.

Materials such as these have revolutionized house waterproofing. Much more resistant to moisture infiltration than old fashioned tar paper, these materials substantially improve the energy performance of the house, as well. By reducing the air infiltration in exterior frame walls, particularly on windy days, these high-tech house wraps help the building insulation remain effective. All insulation works on the principle of dead air being the actual insulator. The insulation simply keeps the air still so it can insulate. You can imagine that if air is moving around in the wall cavity, the “R” value (insulating value) is going to be lost. The house wraps keep wind from penetrating the walls and compromising the insulation’s effectiveness. House wraps will save you a lot of money in heating and cooling costs.

When the roof is completed, this house will be fully watertight. Notice the special tape around the windows and doors.
When the roof is completed, this house will be fully watertight. Notice the special tape around the windows and doors.

When the windows and doors of a house are installed, the house wrap is taped to the window and door frames with special tape to insure a tight seal. When this is done and the roof has been installed on the house, the house is watertight, regardless of whether any of the siding has been installed. The siding material is there to protect the house wrap, deflect the heavy weather, and for looks.

If your house is being built in a cold climate and you are worried about brick, stone, or stucco being installed in freezing conditions, you don’t have to delay the start of construction. You can begin the house, provided weather permits the foundation to be built, and let the builder frame everything. He can install the roofing, install the windows, and wrap the house up with one of the house wraps. The house will be watertight and the interior construction can continue. The masonry on the exterior can wait until warmer weather without delaying the rest of the construction.

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