How to Build Houses to Prevent Paint Blisters and Stains on Exteriors and Prevent Many Other Troubles

\Aralls and non-wood siding or brick exteriors will become damp if the applicable precautions described herein are not followed.

It is easy to guide your builder customers so that they clo not have troubles with paint blistering and staining. Just get them to observe the following' recommendations. It will be profitable for lumber dealers to stock and sell the various products mentioned hereafter.

RECOI\4MENDATIONS

1. Wide tight eaves and roof extensions on gable ends are important. An overhang of 18 inches or more is recommended.

2. Extended roof sheathing and paper beyond outside of wall siding so that any condensation on underside of roofing material runs off outside of siding and not into stud space or back of siding. Lower edge of frieze board to be against outside of siding, not on top of it.

3. In Canada and in any p'art of the United States where it gets cold enough to install insulation in house walls, a vapor barrier with a vapor transmission rate of less than one perrn should be applied properly on the warm side of all exterior rvalls.

4. A similar vaDor barrier should be installed on the underside of an insulated ceiling of a room below an unheated attic.

5. Ventilate unheated attics, especially those that have insulated floors.

6. Ventilators from bathrooms, kitchens, washing and living areas should be open to the outside-not into the attic.

7. Plaster should be dry throughout its thickness before applying the second and third coats of paint on the siding. This is not so important if a good vapor barrier has been installed in the walls behind the plaster. Leave windows open during drying of plaster.

8. Properly install flashing over all water tables and drip caps at doors, windows and elsewhere, extending metal down over edges and ends of well sloped tables and caps to prevent water getting back of siding or frames of doors or windows. Edge of siding should not rest down tight against near-level water tables.

9. Make sure the sheathing paper is not a vapor barrier.

10. Be sure sheathing is dry when siding is installed

11. Prevent movement of moisture from crawl spaces to stud spaces by placing a soil cover with a vapor transmission rate of one-half perm or less on the ground. Lap the joints about four inches and place tight against all walls and piers. First remove all sharp stones and pieces of wood off the ground. When soil covers are used in crarvl spaces FHA requires at least two wall ver-rtilators with a net free ventilating area of not less than 1/1500 of the area of the crawl spaces. Houses with basements will be drier and the basements more suitable for living quarters if a similar soil cover is placed under the basement floor and extending up outside of foundation wall to grade level. and

Vegetation should be at least twelve inches from walls. Earth around houses should be sloped away from the walls to prevent accumulation of rain water.

For bevel siding use clear, vertical grain-no knots. -t'or Devel When flat-grain drop siding is wanted specify that the oattern or face side be run on the "bark" side of the pattern slde board-and no knots.

Use siding 'ivith a moisture content of 9 percent to 14 percent. Keep siding dry in storage and at building site. Generously coat the backs and ends of siding with a good water-repellent preservative unless the stock has been dipped in such a solution previously. In any case siding ends freshly cut at job site, should be coated liberally with a water-repellent preservative. Do not back prime u'ith ordinary paint. If lvater repellent gets on face of siding, make sure it is thoroughly dry before applying first coat of paint.

19. Use hot dipped galvanized, aluminum or stainless steel nails.

20. Place nails in thick butt of bevel siding so they just miss or nick ttre tl-rin edge of piece underneath. In board and batt siding, do not place nails on extreme edges of siding, as this could cause splitting due to holding the siding too tight against shrinking and swelling.

21. Encls of sidings against sloping roofs should be trimmed back at least 3,4" and should be treated with a waterrepellent preservative.

22. Leave no open joints when installing siding. When ends are butted against corner boards, casings and er-rds of acljacent pieces of siding, including mitres, nrake sure thev are really tight. Experience has showtt that placing the corner boards over ends of drop siding keeps tl.re encts drier. NIetal comer pieces must be tight or they will cause decay and paint trouble.

23. Lowest course of siding should be at least 6" above ground-on house, garage, and breezeway.

24. Dip treat all door, window and screen frames rvindows in a u'ater-repellent preservative. Slant all outside vi'indorv sills to the outside. Coat steel, copper and bronze screens lvith-paint, screetl enamel or varnish.

Make garage cloors with smooth outside surfaces, with boards running vertically and rvithout cross braces on the outside.

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Set porch columns on metal stools and ventilate columns at top and bottom.

Don't paint on a damp day or too early in the morning lr'hen der,v is still on the wall, or on too cold a day. If siding is rained on, let it dry thoroughly befoie applying any paint coat.

Try to follow the sun arouncl the house ; that is pair-rt all area after the sun has passed over it. Use a good paint with ample thickness of prime coat to prevent derv or rain getting through to wood to cause staining.

32. In damp Iocations where there is danger that mildew rvill occur on the paint, a paint with a mildewcide in it should be used.

In industrial areas where there is a sulphurous atrnosphere use a paint lvithout lead in it. Apply seco'nd coat of paint rvithin two weeks of appli- cation of prime coat if there has been good drying weather.

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For best results, total paint thickness should be about 5 mils made up of 3 coats. Prime coat should be l)/a to ll mils thick with balance of thickness evenly divided between the two remaining coats. When repainting, use a paint that is compatible with the paint already on the siding.

Do not paint over too many layers of old paint. For remedies for paint blisters and stains on existing houses, see "How l'o Locate Causes of Paint Blisters and Stains on Siding."

Redwoo<l pipe in the Philippines and Hawaii has given service for 30 years and more because of the natural resistance to decay and termite attack afforded by natural chemicals in redr,vood heartwood.