rainwater fittings and your Evesham property
7th February 2011
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Rainwater Fittings.

Given little thought, and not really held in any sort of reverence, one of the most important components to your house is the rain water fittings, otherwise known as the “gutters”.  My article was prompted this week, because I had helped over see the building of an office extension a couple of years ago, we had fitted upvc gutters and down pipes, and this week when I made a monthly inspection, the gutters had become twisted. They had not stood the weight of the loadings imposed by the snow and ice received before Christmas. The gutters had to be replaced.

I also have had to replace the bonnet on my car this week, as damage to it was caused by snow and icicles sliding off the roof and landing directly on the bonnet. Not a good week, and certainly the cold weather experienced at Christmas is regarded as being fairly rare these days, in terms of designing gutters. If we have a greater occurrence of heavy snow falls and prolonged cold periods, we may have to start to copy the Continentals, who make extensive use of metal guttering, and very short down pipe spouts, which act to shoot water away from the building as quickly and efficiently as possible.

It is a very good idea to take a rain check of your house.  If it is raining heavily, go and take a look at the gutters, and see where the water is running to. If it’s not raining and you see green slimy walls, stains or splash marks on the external wall surface, or if rendered, blown or mouldy plaster, then the odds are on that your gutters will need an overhaul. I quite often find plants growing in the gutters, rooting nicely in the detritus generated from years of leaves collecting in the gutter, rotting down to create a good compost.  That kind of deposit in the pipes is hardly conducive to efficient removal of water from the roof surface.

Other faults, particularly in upvc guttering is the phenomenon of sagging. Upvc gutters should be supported by brackets at no more than one metre gaps. If the brackets are any wider, the gutter will sag under the weight of water sitting in the pipe before entering into the down pipe. Check the fall on the gutter, it is supposed to have a gentle slope towards the downpipe.  Sometimes I have seen them slope in the opposite direction, and Confusus was right when he said that water doesn’t flow up hill.

The fall on a gutter should be between 10mm and 25mm per 3.5 metre run or for the old fashioned amongst us, 1” per 11 feet of gutter pipe. It is important to get it right because if the run is too steep, water will overflow at the downpipe outlet, too shallow and a build up of sediment and water may cause overflowing. Also check that the stop ends are present on the gutter. Quite often they are missed off by the builder. If missing, water can pour out of the gutter, and look like a mini water fall.

Equally crucial is the manner in which rain water leaves the edge of the roof. In modern roofs, there is a layer of sarking or under felt laid directly under the roof tiles.  At the roof edge, the sarking felt should sit directly above the gutter, so that the gutter will catch any water leaving the roof, without it pouring over onto the brick walls. Gutters should normally be positioned centrally under the roof edge, and no more than 50 mm or 2” below it. If the gap at the end of the gutter is too large, water pouring off the roof may overshoot and run down the brick walls. Gutter pipes are normally supported by either metal or plastic brackets fixed either to fascia boards, the brick walls or even the ends of roof joists.

My other pet hate on roof design is the ubiquitous valley gutter.  I shiver at the thought of the grief they can cause if poorly designed and maintained.  They are quite commonly found behind parapet walls, they may be constructed on top of party walls, and they all have one very common characteristic, they are normally invisible from the ground. They are normally created out of wood, joining two pitch tiled roofs together. They are then sealed with lead sheeting, which “forms” the gutter. Over time, the lead sheet oxidises, and eventually splits, allowing water to soak through and rot the timber underneath. They also have a happy knack of collecting leaves, the build up of which can create a dam, and you can guess the eventual outcome, brown staining on the ceilings underneath. If you have a valley gutter, it is a very good idea to inspect it at least once a year, particularly after autumn when the leaves have fallen.

This article would not be complete without a mention of shared drainage schemes.  Quite often in terraced or semi detached houses, a single gutter system will serve both properties. So you and your neighbours will be mutually dependant on each other.  If all is working well, this isn’t a problem.  If the system blocks up, or the system is so old that it has reached the point when replacement is inevitable, then you will have to lias with your neighbour. It is a good idea to know your legal responsibilities on the building, perhaps a quick telephone call to your solicitor will provide this information, or if you have your registered title deeds, the covenants affecting you will be listed on the document. It is always a good idea to talk to your neighbour, and work together.  This invariably costs less in the long run.

It is essential to have good rain water fittings. Where they fail, you end up with damaged brickwork, water erosion can be very damaging, and wet bricks are vulnerable to frost damage called spalling, and internal damp problems.  As always with property maintenance, a stick in time saves nine, and that can have a dramatic effect on your pocket, when it comes to rectifying the problem.

By Tony Rowland - Timothy Lea & Griffiths Evesham



About the Author

Alan J

Member since: 10th July 2012

Whilst running The Best of Evesham I am also locally focussed on doing what I can for the local community in profiling what is going on.A prolific user of Social Media-We offer Social Media Management...

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