How to Stucco a House

How to Stucco a House

Stucco makes a very good exterior wall finish. It is applied over lath, which can be made of zinc-coated, or galvanized metal, galvanized woven wire fabric, or galvanized welded wire fabric. These mesh materials allow the stucco to go into the openings and adhere well to become stronger. The wire needs to be galvanized to help protect against rust. Different gauges of wire are available but the most commonly used is eighteen gauge wire.

The lath is kept away from the house frame sheathing by about one quarter of an inch. This allows the stucco to be strongly imbedded. Plywood sheathing, then building paper, metal lath and then the stucco is applied. The stucco is a plaster type material that is made from cement, sand and lime. Thin coats have to be applied. The first coat needs to be forced into the lath and worked well with a trowel so all points of the mesh are embedded within the plaster. Three coats are applied to a total thickness of about one inch.

There are commercially prepared stucco mixes, but you can mix up your own by using three parts sand, one part portland cement and hydrated lime to ten percent of the cement by volume. After applying the three layers the stucco will have to be kept wet to prevent a too fast dry time. The slower it dries the stronger it will become. If the stucco is in a very hot sunny area it should be shaded in some fashion to keep it out of the heat. You want the stucco to set and become hard very slowly. Any commercially prepared stucco that you buy should be applied by the manufacturer’s instructions. All brands are different to some degree.

Before applying stucco, you want the sheathing and the house walls to be prepared for that kind of application. If the stucco is being put onto a house that is two stories tall it is recommended that balloon framing be used. The more joints there are in the framing, the more chance there is that the stucco will crack. This happens because of the movement of the sills and plates. Sometimes an ugly bulge can appear in the stucco when a house settles. So be sure the framing is for a stucco exterior.

The mesh lath that is used should have once inch minimum openings. Probably a two-inch opening is the maximum that should be used. The backing paper behind the lath should be waterproof if possible. Nails that are specific for stucco mesh should go into the wood sheathing at least three quarters of an inch. This keeps the stucco wall attached safely to the house. Use galvanized furring nails, metal furring strips or self-furring lath for proper spacing of the lath away from the house wall. A stucco wall finish is very heavy, so plan accordingly when framing and building the house.

Do not apply stucco if the weather temperature is less than forty degrees. Watch someone else apply stucco before attempting it yourself.

You can leave stucco the natural cement color or color it any color you prefer. Some good colors are sunset colors like yellow or a pink orange. Also beige is a popular color for stucco homes. Of course white is always good for any home.

The main problem with stucco is cracks. They can easily be fixed and covered over although sometimes the problem lies underneath and more cracks will appear if the main problem is not corrected.

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