Renovation of painted surfaces exposed to weather conditions.
Wood exposed to the elements, mainly rainfall and solar radiation, it will change faster than wood indoors. It is impossible to create a durable protective coating. Sooner or later, water and ultraviolet rays will break any protective coating. When deciding to clad external walls or their fragments with wood, always keep in mind their maintenance three times each, four years and in the longer term. More than one owner of a single-family or recreational house has experienced great disappointment, when after a few years he stated, that the wood-clad exterior walls are damaged, the varnish peels off and breaks off, and the wood becomes black under the varnish. Because the conservation requirements of wood panels exposed to weathering are significant, we should choose the appropriate type of wood for them and lining them, these planes if possible, which are least exposed, e.g.. leeward walls, shaded etc..
One basic rule should be kept in mind when performing maintenance, that the varnished coating should be renewed before it is damaged, i.e.. exfoliation, wood splitting and blackening. Preventive surface renewal is the only way to protect the wood from deterioration. That is why we renew varnished surfaces after three years, and exceptionally exposed to destructive weather conditions - after two years.
Renewing the coating is not just about covering it with a new layer of varnish. The handling cycle is a bit more complex. First of all, choose a period of good weather, when it's not raining and it's dry. First, the wood must be cleaned of dirt and grease, which adhere well to the painted surface. It is best to use warm water and shampoo for washing. After the washed surface has dried, it should be sanded with sandpaper 80 or 100. The rounded edges are sanded very carefully, in order not to peel off the old layer of varnish in this particularly exposed area. After sanding dust, wipe off the dust with a cloth or chamois leather. Only the prepared surface should be varnished twice with the same varnish, which was used originally.
This procedure applies only to non-cracked coatings, not peeling, under which the wood has retained its natural color. If, on the other hand, we neglected preventive maintenance and some of the surface has already been damaged, restoration is much more complex. Damaged places should then be ground down to wood. Manual sanding is tedious, therefore, it is better to use a drill with a friction disk for this purpose. Places unavailable, like grooves, side planes, etc.. it is cleaned with a scraper or a plow with an elbow. Clean the sanded surface of dust. We blow dust out of hard-to-reach places. The renovation coating in these places is made similar to a new one, i.e.. we will tear it first, wiping off the excess varnish from the varnished edges with a rag, and after the varnish is dry (usually after 24 hours) we apply at least three layers of varnish. Good drying of each lacquer layer and sanding of at least the first layer is a necessary technological requirement. In the course of preventive maintenance, we will find out, that wood-lined exterior walls are often difficult to access, that in many cases a ladder is not enough to paint them and scaffolding has to be built, and then we come to a conclusion, that at the design stage of the facility, not everything was carefully thought out by us.
If the maintenance has been so neglected, that the varnish peels off the entire surface, and the wood darkened, then the only solution is to remove the entire carpet, its reworking, painting and assembly. And so, the procedure is the same as for a new carpet.