Roof guttering sagging and Leaking joints
Coping with sags
If a section of guttering has sagged, making it lower than the top of the downpipe, the water will not drain away properly. And you will be able to see this from puddles of water collecting in the guttering itself. You must decide whether to raise the sagging section, or lower the mouth of the downpipe to bring everything back into line.
If you flex cast iron guttering more than about 25mm (1 in) you’ll break the seal on the joints, causing a leak. So choose the option that involves moving the guttering least. In order to reset the guttering to the correct gradient you’ll need to fix a piece of string taut between two nails hammered into the fascia board.
Cast iron guttering repairs
You can then use this as a guide as you reposition each gutter support in turn. Leaking joints Joints in cast iron gutters are made by overlapping the two lengths of gutter, and bolting them together with a layer of sealant in between to form a watertight sea!. As this sealant begins to deteriorate with age, the joint starts to leak. To make the repair, first remove the bolt holding the joint together. Often this is too rusty to undo, so hacksaw off the bolt between the nut and the guttering, or drill out the rest of the bolt. Lever the joint apart with an old chisel, and scrape away all the old sealant. Clean up the joint with a wire brush, then apply a finger-thick sausage of new sealant and bolt the sections back together using a new nut and bolt and a couple of washers. Scrape off any sealant that has oozed out before giving the repair a coat of bitumen-based paint on the inside of the gutter.