How to remove old gutters and rain pipes and replace with a new plastic rainwater system.
Plastic gutters and downpipes
By far the most common form of rainwater system for domestic use is now made of plastic. This has many advantages – lightweight, easy to cut, easy to fit, durable and maintenance free.
It is essential to use a suitable and stable means of access when working above ground level.
Removal of old rainwater goods
When dismantling an old system, great care should be taken. Many are particularly heavy.
To be safe, it is best to have an assistant help you with this and use a rope to lower the old sections to the ground.
Choice of new rainwater system
There are many different sizes available and you should select one at least as big as the old system. For new work, you will need a system whose capacity is sufficient for the size of roof being drained. Your merchant will be able to advise on this. An undersized gutter will overflow in heavy rain.
Measure the overall length of gutter required. Divide this by the standard gutter length. Always round your answer up so that you will have sufficient for the job.
Do the same for the total length of the downpipes required. Then make a note of the number and type of fittings needed: brackets, joining pieces, stop ends, outlets, stopend outlets, pipe clips, bends.
Installing new gutters and downpipes
Inspect and, if necessary carry out repairs and redecoration of the fascia boards – they are much easier to work on without gutters in the way.
Take an offcut of guttering and mount it on a bracket. Hold this against one end of the fascia board as close to the tiles as practical. Mark the top of the bracket. If this is too awkward, mark the bottom, but remember this when you are fitting the rest of the gutter. Tap in a nail and attach a piece of string. Now move to the other end of the fascia and, pulling the string taught, use a spirit level to position the string horizontally. Tap in another nail to secure it.
This process should be repeated for all the fascias.
Now, use a plumb line to mark a positions on the fascia which are vertically above the gullies or other rainwater drainage points on the ground. These are the positions at which the gutter will need to be lowest.
The fall or incline of a gutter will need to be at least 1:600. This means that for each 3m length a fall of 5mm is needed.
Where there is one outlet at the end of the fascia, calculate the fall needed for the length and lower the string line at the outlet end.
Where there are outlets at both ends, tap a nail in to hold the string at the middle. Lower both ends to suit the length from the middle to the end of the fascia.
Where the outlet is to be part way along a fascia, lower the string at this point to suit the longest length and support with a nail.