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Roof Types
Built Up & Tar Roof Maintenance Guide

Many contemporary houses these days like to showcase a low slope roof, and so it is becoming highly sought after. However, many traditional roof materials are not at all suitable for this kind of low slope, and so the use of tar and gravel materials is becoming a lot more common. Known in the trade as “Built up roofs” or simply “Tar & gravel roofs”, they consist of many layers of tar paper and asphalt that is fixed to the surface of the roof by using an application of molten asphalt. After being laid on the roof, these asphalt and tar layers will be laminated before being covered with gravel, known as ‘shingles’. The shingles act to hold down the layers and it also offers good protection against degradation and UV rays from the sun. A portion of this gravel will embed itself into the hot and sticky asphalt, while some of it will stay loose on the surface of the roof. Built up roofs have a life expectancy of anything between 10 and 20 years depending not only on the design and quality of workmanship, but also on how well maintained they are.

Complexities of Built Up Roofs

Despite the durability of built up roofs, they are nevertheless quite susceptible to leakages. This is due to the tar and asphalt layers being sensitive to penetration. Also, built up roofs have to be capable of moving and reacting to climate changes, just as membrane roofs are. Most often, deterioration will occur in the areas of roof around chimneys, flashings, eaves or sometimes the extra roof planes. As well as this, heavy winds will sometimes strip the built up roof of its gravel layer and leave the surface exposed to the elements. This deterioration leads to leakages very quickly. As well as these problems, older tar and gravel roofs will suffer from asphalt blistering. The easiest of solutions to repairing these leaks often highlight the need for patches of the roof to be replaced. However, this can do more damage than good. The biggest problem is that built up roofs do not last as long when multiple layers are applied, as they can become distorted due to the extra weight. Also, the need to walk or crawl over the built up roof can damage the layers of asphalt and tar even more, causing it to crack and potentially leak even more. Therefore, unless you are extra careful, and unless you can carry out maintenance aimed at preventing damage rather than waiting for it to happen, you are going to have to replace the whole roof at a great cost. With care however, it is possible to avoid all of this.

Cleaning a Built Up Roof

The roof of your house is the number one defense for your home against the extreme forces of nature. It is exposed to an incessant onslaught by the elements and needs to withstand a lot of punishment. There are always environmental factors that it has to struggle against. Some of these factors will be things you know about, for example storms and ice, but others such as plants like mildew and small living creatures may go unnoticed for a long time.

Together, all of these factors contribute to making your built up roof appear very dirty, because it is just that. A dirty roof will deteriorate a lot faster than a clean roof does, and so it is essential to carry out regular cleaning of your roof. Cleaning the roof shingles can be a taxing job however, if you don’t know about the correct methods.

To clean the roof shingles, it is really quite simple, once you know how. The answer is to get up to a good vantage point and use a pressure washer to blast it clean. When you do this, take note that you must start at the very top of the roof, and blast the roof clean in a horizontal fashion. You must also make sure that the pressure washer is always pointing DOWNWARDS while you are cleaning the roof. This allows the water and dirt to run off the roof, and means that it cannot travel up through the gaps in the roof and leak into the house below.

To clean the roof shingles, it is really quite simple, once you know how. The answer is to get up to a good vantage point and use a pressure washer to blast it clean. When you do this, take note that you must start at the very top of the roof, and blast the roof clean in a horizontal fashion. You must also make sure that the pressure washer is always pointing DOWNWARDS while you are cleaning the roof. This allows the water and dirt to run off the roof, and means that it cannot travel up through the gaps in the roof and leak into the house below.

Cleaning Roof Shingles

Black streaks appearing on your built up roof are a certain sign that there is algae growing on the surface. What they actually mean is that the algae have invaded the tar shingles. This is not a disaster, yet it needs to be given attention as soon as possible. If you don’t clean it as soon as you can when you first notice the black streaks, it could well lead to permanent staining of your roof, marring the overall look and impression of your home.

If you are using fiber glass shingles on your roof, be aware that these are an especially conductive environment for algae growth, as they are sufficiently moist enough to promote its rapid growth. This is why algae grows so rapidly on fiber glass roof shingles, and why they are so commonly afflicted by this damaging growth. Cleaning the roof with just pressure washer might not be enough to clean the algae from an infected roof. A much more successful method is to use specially formulated chemicals with the pressure washer to clean it. One of the best chemicals available for this task is sodium carbonate and oxygen bleaching agents. Bear in mind, it is vital to use only bleaches that are oxygen based, never chlorine based bleaches. This is because a chlorine based bleach can easily damage the roof shingles permanently, as well as anything in your garden it comes into contact with. Chlorine bleach can also damage the roof’s guttering, and it is even harmful to humans. For this reason, chlorine bleach should be avoided at all costs.

Copper shingles are a very popular choice with an ever growing number of households. These shingles provide a very nice, stately home appearance and greatly improve a house’s aesthetic value. While they do look really great when first installed on the roof, they can deteriorate very quickly if they are not looked after. Heavy maintenance is therefore required in order to keep the appearance pristine. As time passes, copper shingles will become blackened and take on a dull, grimy appearance, making your house look quite ugly. Cleaning of copper shingles can take a long time and is a very tedious job, not to mention it is very difficult to do at all! In truth, copper shingle cleaning should only ever be carried out by a professional roof cleaner. For anyone who has already spent an arm and a leg on copper shingles, then a little bit more spent on a professional cleaning job is going to be a very worthwhile investment.

Built Up Roof Inspection

A built up roof should be checked at least once every six months for signs of wear and tear. The best times to do this are Spring and Fall, just after the roof has been exposed to extreme weather conditions. It may also be valuable to check the roof after any extreme weather event.

It’s very important to maintain a record of the state of your built up roof. After the first check, carefully mark on a plan, or else right down the exact location of any defects that you can find. With this record, it is possible to compare the situation every six months, following each and every inspection. This way you can get a clear idea of if and how your roof is deteriorating.

The inspection should begin with you checking the underside of the decking if it is accessible, followed by a check of the outside of the building. The things to look out for are stains, cracks, rusting, wets spots, efflorescence and spilled mortar. Also check for any other signs, including deterioration and excessive moisture. These observations should give you some good clues as to what problems the roof has, if any.

Once you have checked outside, you need to get onto the roof for the final inspection. The key here is that you carry out your checks thoroughly and with the utmost care and attention. Also be warned that you are likely to get very dirty.

Problems to Look Out For

Despite their durability, leaks almost certainly will occur in built up roofs. Most often these leaks occur near to where the lead flashing is, for example near where the chimney and the roof connect. Other roof panes and eaves are also problem hot spots, so they need to be checked thoroughly. Another area that leaks can happen is where gravel has been removed by heavy wind, exposing the roof surface to the elements.

If yours is an older roof, you should also look out for areas where the asphalt and tar layers have blistered or where layers have separated. It’s a good idea as part of your preventative maintenance program to keep the roof covered with shingles. Make sure that there aren’t any bare patches anywhere on the roof. This will help your built up roof to survive for much longer.

Repairing a Built Up Roof

A small repair job for a damaged section of a built up roof is easy enough to carry out. The basic idea is that you cut out the damaged section and then replace it with a new piece of asphalt. To carry out the procedure correctly, the following steps should be observed:

A small repair job for a damaged section of a built up roof is easy enough to carry out. The basic idea is that you cut out the damaged section and then replace it with a new piece of asphalt. To carry out the procedure correctly, the following steps should be observed:

Your built up roof should now be fully waterproof again and ready to serve you once more. However, if problems or leaks persist then it is definitely recommended that you get a professional roofer in to have a look.