Home Detailed application Technical Detail

Technical Detail

Pre-frabricated valley gutter - Technical Detail


A valley gutter area can be pre-fabricated if the area is small or difficult to access. This is constructed from GRP edge trims bonded together with GRP bandage. For any right angles use an AT195 int (for abuttingsteps) or AT195 ext (for capping steps). F300 flat flashing is used for any flat section and to run up underneath the first row oftiles or slates that drain into the gutter. Use 100mm bandage and catalysed roofing resin to join each of the sections together. This may need to be completed in stages joining each length on a flat surface and allowing it to cure before moving on to then ext. For larger or more complex detail extra care should be taken using two bandages (which can be applied at the same time) to join trims together if extra rigidity is required.

Alternatively trims can be joined together first with PU adhesive before bandaging.

If the gutter is not completely flush or the walls are too tall to prefabricate a stable construction, prefabricate two halves which can be aligned to the sides of the gutter and joined together onsite.

The At195Int/Ext is very flexible and will easily fit most obtuse angles. If the angle is steeper than 450 use a D260 fillet trim andsand the underside of the trim to ensure a good bond.


Remove the first row of tiles or slates if required. The flange from the top of the prefabricated gutter (F300 section) will need to sit comfortably under the first row of tiles allowing for 150mm overlap.

The pre-frabricated section can be adapted on site to suit the application using an angle grinder, sections of F300 can be used to patch fixing them to the substrate and using PU around the perimeter (the underside of the trim will have to be sanded first). The perimeter will need to be bandaged to bond the trim to the surrounding area.

The gutter will need to be mechanically fixed to the underlying substrate ensuring good penetration with a positive fixing (ringshank nails or screws). This should ideally be done in a straight line if possible.

The fixings should then be all be laminated with a 75mm bandage.

More Articles...

We use cookies to improve our website and your experience when using it. Cookies used for the essential operation of the site have already been set. To find out more about the cookies we use and how to delete them, see our privacy policy.

I accept cookies from this site.
EU Cookie Directive plugin by www.channeldigital.co.uk