Complete failure may result if the work is subjected to rain or dust or other extremes of temperatures before it has had time to skin over or dry to a reasonable degree. The possibility of damage decreases as the period of hardening extends, but it will remain a feature until the material has dried for some weeks.
This, then, is the problem which presents itself when exterior house painting is to be carried out.
Few places even in the U.S. enjoy constant good weather for more than a few days at one time, and the choice of suitable weather is limited by extremes of heat or cold.
Winter being both cold and wet, is unsuitable.The excessive heat of midsummer on freshly painted surfaces is far from ideal and, indeed, rather detrimental to the elasticity of the film.The unpleasant working conditions on hot, dusty days create a personal point against extreme hot weather for outside work. This leaves the seasons of spring and autumn in which to concentrate on this work. With spring come showers which are not ideal for exposed work. Autumn, with its mild, even balanced climate, is probably the best but due to the wide range of weather variation over a period of years, the choice is really better left to the individual when the work is being planned.
Most satisfactory conditions are medium to warm weather without sudden changes or drops in temperature. Strong, windy weather should, be avoided as the dust will be blown over the wet, painted surfaces.
A little discretion is always advisable, and many of the attendant risks can be eliminated by the careful selection of the parts of the work to be carried out, bearing in mind the weather aspect.
It is most unwise to paint over damp or wet surfaces because it will seal down the moisture and prevent the paint from adhering firmly to the surface, thus creating the problem of paint work blistering when exposed to the heat of the sun.
House Repairs
Most houses will require some building maintenance or experience on how to paint a house prior to the paint work being done. The job should be closely inspected for faulty timber or corrugated iron, etc. Any seriously affected parts should be cut out and replaced with new materials.Galvanized roofing should be inspected and any loose sheets renailed. Quite often the nails will “spring” or come loose due to the expansion and contraction of the roof surface, and care should be taken to knock back these nails. Rotting timber should be cut out and replaced with new wood, neatly fitted to the opening.
Borers
A check should be made of all timbers for borers to prevent undetected damage occurring. If there is any sign of them, the timber should be treated or cut out and replaced. There are a number of spray treatments which are most effective and well worth the money expended, A periodical check-up on this point is advisable, because a good deal of timber being used in homes of today is likely to be affected, and much of the strength of timber will be lost if borers are allowed to continue.
Exterior house painting tips can make a job go much smoother.
Fly Wire Screens
These should be taken down from the windows to allow free access to the work for exterior house painting. If the screens are stored away in the garage or workshop they will provide a job for a wet day.
Cleaning Windows
Although many people overlook this fact, it is really vital to see that the glass of all exterior windows is thoroughly clean prior to painting exterior windows. Dust, dirt and soot from surrounding atmospheres collect on the surfaces of the glass, and if this is not removed the fresh paintwork beneath will be stained and damaged.
Rain beating on the glass will wash down the chemically active residue which attacks the paint work, causing dark stains to appear.
Trimming trees and shrubs near the building will save much time and damage during the progress of exterior house painting. Overgrown shrubs near the work will interfere with the movement of scaffolding. A good deal of damage will result and it is wiser to carefully trim back the greenstuff than to have them broken.
Wrappers lightly laid over the top of the most important shrubs will protect them from splashing. Wrappers and drop cloths should be used whenever necessary to ensure clean working surrounding paths, verandah doors, etc, will be saved from damage through spotting, etc.
Painting a Metal Roof
Although structurally the roof is more or less an independent section of a house, it would not be wise to consider it as such where exterior house painting is concerned, for it is better to prepare for painting galvanized metal surface before working on lower areas, so as to avoid the risk of damage through splashing or spilling paint on to completed work below.
A pair of rubber shoes will make roof work more comfortable, and will carry a greater sense of security to the wearer. When ready for the actual work, the roof ladder should be laid into position with the top sheet resting upon the back edge of the ridging.The first step is to go over the surface of the iron with a hammer and knock down any loose sheets. Points should be made that all roof nails in galvanized roofing iron should be put in through the tops of the corrugation, the flanged heads of the nails covering the hole in the iron created by the body of the nail, thus making a waterproof cover which prevents rain leaking through. Nails put through the hollows of the corrugations will most certainly cause leaks to develop.
Fresh Roofing Iron
Fresh roofing iron is smooth and very often greasy, and so does not present an ideal surface for paints when exterior house painting. Because it fails to adhere to a smooth surface, the paint will very often peel when exposed to extremes of weathering. A period of weathering of twelve months or more will overcome the diculty. But for individual jobs where immediate painting is necessary, the surface may be cut down with turpentine and emery paper to provide a key for the paint. A more definite and less strenuous treatment is to coat the surface over with a solution of copper sulphate or copper acetate (approx. 8 ozs.to 1 gal. of water), made in earthenware or glass containers. Chrornie acid may also be used. The coating Should be allowed to dry, when it will etch into the surface of the galvanizing, roughening it up and providing a key for exterior house painting.
It is claimed that old style galvanized iron weathered for many years before any rust began to show, whereas in these days the iron shows signs of rusting after a few years. This may seem to indicate a poorer quality of manufacture, but possibly the difference can be more correctly ascribed to the greater number of factories and greater proportion of acid laden fumes in the atmospheres in industrial areas today.
The acid particles, in settling upon roof surfaces, set up a corroding action on the galvanizing, and once this is eaten away the iron beneath quickly develops rust.Generally speaking, the chief reason for painting iron work is to protect the metal from corrosion, and to achieve this object a good deal of care is necessary in the preparation of the surface and exterior house painting.
Rust Removal
No paint, will protect a surface if rust and scale is not first removed. The rust acts as a mask to prevent the paint from adhering properly to the iron and once sealed in by the paint, it will become active under the protecting film. In extreme cases it may rust away entirely without much noticeable action from above.
All rust should be removed, and where large areas are involved, rubbing down with emery paper and a wire brush is the most effective treatment. Old carborundum paper will be found to have a good cutting action.
The process involves going over the whole surface, rubbing and sanding down, then dusting off all loose particles to leave the surface clean.Where the roof has been previously painted, it should be thoroughly sanded down. Then when it has been scoured all over and rubbed down correctly, it should be thoroughly dusted.Although roof surfaces are well away from the general line of vision and close inspection is impossible, any lack of attention to cleaning and preparation is a very short sighted policy.
One of the greatest aids to the durability of roof paint is the quick “drain-off” of the rain water, because it will lessen the risk of roof rusting. The smoothness of the prepared sur face and the paint coat application goes a long way toward promoting this quick drain action.
Leaky Galvanized Iron
Where rust has been active for a long period it may eat right through the corrugated sheeting. Any badly affected places on the roof will develop into leaks which should be rectified before any painting is done. If large areas are rusted through there is little alternative to resheeting. Small areas can be effectively sealed by coating them over with one of the plastic bituminous substances marketed for this purpose.
The iron should be cleaned and the material applied with a clean putty knife to the dry surface, carefully building up the thickness of the coating over the affected places to approximately 3/16in. It should be smoothed over to allow the free drainage of rain water, and should be thinned out at the edges to avoid ridges which would hold up the flow of water down the corrugations.
Mastic Canvas
Another treatment for small areas is the use of mastic canvas. This can be prepared by building up coatings on calico with pliable paint until it becomes thoroughly waterproofed. The canvas is then attached to the iron by the aid of a thick, sticky paint, which acts as an adhesive. The material is pressed into position around the corrugations, making sure that it lays fiat to the surface. Especial care is needed at the edges. A final coat of paint is then applied over the top of the patch and extending over on to the iron surrounding it.