Roof Tiles
In a new building or building less than 20 years old it can be expected that the material quality of the roof tiles should be of a very good standard. There may be physical damage that needs to be identified as a result of tradesman traffic, pests or overhanging tree limbs and in worst cases there may be a structural failure of the building that contributes to tiles breaking or becoming dislodged.
But it is in older homes over 25 years of age, that significant attention needs to be provided towards identifying the material condition of the individual roof tiles and the condition of the tile surface. Particularly for concrete tiles which once becoming porous suffer an increased rate of deterioration unless a surface treatment and new sealant has been provided.
Not all roof sealant products and services are of the same quality and some times roofs have been sealed when they should really have been replaced. This is obvious when tiles that have been sealed within the last 5 years are already displaying mould growth, discolouration of the sealant and are very brittle.
Mould and water marks in the ceiling and eave lining are obvious signs of a failing roof. In the early stages of roof tile failure there may be no visible signs within the house and it requires a look into the roof space for an accurate assessment.
It is not uncommon in the early stages of roof tile failure, when only minor levels of dampness penetrate the roof, that the roof insulation absorbs the dampness, therefore delaying the "appearance" of damp damage to the ceiling plaster.
The mortar pointing which is the sandy cement mixture found along the edge of roof lines, ridges, hips and valleys acts to hold the tiles in place and is an important element of a roofs overall performance. This is the weakest link in the performance of a tiled roof and typically requires major servicing every 10 years. The cost of such service for a 20 square home would vary from $500 to $1,000 depending on the roof design. Expect additional expense if the replacement of rusted valley iron and flashing materials is required.
Typically roof tile manufacturers provide a 10 year installation guarantee and a material guarantee of 30 years on concrete products with 50 years on most terracotta products. To strip and replace the roof tiles over a typical 20 square home the cost for concrete tiles would be approximately $14,000 - $16,000 and for terra cotta tiles it would be $18,000 - $20,000.
If you apply the appropriate time frame to the roof type of your house purchase you can figure out just how important previous maintenance standards and the likely need for future expense will be.
Article written by Jason Wier B. Eng (Building) principal Inspection Angel 2007.
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