Sealing horizontal gutter runs / joints

Discussion in 'Landscaping and Outdoors' started by DIYDave., Jul 7, 2021.

  1. DIYDave.

    DIYDave. Screwfix Select

    Hi all
    Running guttering along both sides of a pent roof shed, just want 1 downpipe so planning on joining the two gutters along back of shed with a horizontal downpipe (at a slight angle) and joining with a downpipe branch

    I know previously when using guttering fittings horizontally, although they fit tightly together, they tend to drip (realise this is just for a shed but ….. !)

    Best to join using silicone or solvent weld pipe cement ? I know the pipe cement only works with certain types of plastic and don’t know the technical difference between gutter plastic and solvent weld pipe

    Access to pipe not a problem as fitting leaf guards to gutters so future blockages I can’t envisage happening - or just blast with the hose : jet wash

    Any suggestions to best stop these fittings from leaking when used in a slightly unconventional manner (ie, not the usual vertical plane)

    Thanks in advance
  2. Wayners

    Wayners Screwfix Select

    Gutter joins on rubber gasket so it can move. I've seen gutter slowly walk 100mm or more opening up joints as it expands and contracts on brackets, so I add a stainless screw near the top to hold when I fix those.

    There are gutters than are modeled on site that can be as long as the roll and it's a mystery to me why more don't use that but off topic a bit. Must be 100s of metres long in single run.

    Use polymer or hybrid gutter sealant mastic for leaks / glue but better stick with the proper gutter rubber joints so it can move with heat at cold weather. Silicone only lasts a short time because of the movement. Often just removing rubber and a clean fixes
  3. DIYDave.

    DIYDave. Screwfix Select

    Thanks Wayners but perhaps my thread title was misleading somewhat ?

    It’s not the issue with joining the actual runs of guttering or using say a running outlet, union etc, I know these fittings all come with the soft rubber seals

    It’s joining the 68mm downpipe and associated fittings I need, such as 90 and 112 bends and downpipe coupling - non of these come with rubber seal and not usually an issue as used mostly vertically so water just drops down due to gravity !

    It’s when they’re used horizontally that they leak I’ve found - and that’s using all same brand downpipe and fittings - fit tight but leak

    Not really designed to be used horizontally as the male part of fitting has ridges around it so grips the pipe when inserted - but due to the ridges, they leak (only when used horizontally though)

  4. Peterdevon

    Peterdevon Active Member

    Try gap filling cement
  5. Wayners

    Wayners Screwfix Select

    CT1 or OB1 polymer mastic will do it.

    If a nice tight fit then super glue will stick is vs solvent weld.
    Hard plastic glue from hobby shop is thicker than superglue and will also work well I think.

    Sorry. I never read post correctly.

    I'd go with the polymer I think as a bit more give
  6. DIYDave.

    DIYDave. Screwfix Select

    Thanks all
    Think will go with the solvent weld cement, will also look at the ‘gap filling’ variety, heard of it previously but only ever used the regular SW cement with pipework

    Only guttering to a shed but dripping joints will annoy me ,,,,,,, really :(

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