Flexible Rubber Caps 1 1/2 inch to 4 inch

Flexible Rubber Caps blank off the end of a waste, soil or drain pipe quickly, with no glue and no need to match the original pipe system. The cap slides over the pipe end and a worm drive clip pulls it tight.

What they’re used for

Use them to seal a redundant branch after removing a sink or toilet, cap off a drain while a job is part done, close an old cast iron or clay pipe that’s no longer needed, or stop smells and debris getting into an open pipe on site. Because the cap is removable, it’s also handy as a temporary blank you can take off again later. Use them on drainage only; they are not for pressurised water pipe.

Sizes available

The sizes are nominal. Measure across the outside of your pipe and compare at the counter, especially on old cast iron or clay, where diameters vary.

Fitting tips

Cut the pipe square and clean it so the rubber seals on a smooth, solid surface. Push the cap fully home, then tighten the clip firmly but not so hard that it bites into the rubber. If the cap is going below ground, make sure it’s well bedded and won’t be knocked when backfilling. On a pipe that will be under test, a rubber cap may move, so support it. Clips are sold separately should you need extras. Our flexible rubber connectors section also has couplings, tees and elbows.

Rubber caps at our Glasgow counter

Collect a cap from Plumb Parts at 555 South Street, Glasgow G14 0QX, or order online. Open Mon-Fri 8am-5pm, Sat-Sun 8am-1pm.

Specification

• Material: Rubber
• Connection: Push-on cap tightened by a worm drive band
• Sizes: 1 1/2″, 2″, 3″ and 4″
• Suitable for: Blanking off waste, soil or drain pipe ends, temporary or permanent

Common Questions

Can a rubber cap be taken off and used again?

Yes, slacken the clip and pull it off. That makes it handy for capping a drain while a job is part done, then reusing it on the next site.

Will a cap hold back water under a drain test?

A cap on a pipe under test can be pushed off, so support it or wedge it before the test goes on. For blanking a live soil or drain run for good, check the clip is tight and the cap is fully seated.

Which size do I need for a basin or bath waste?

The 1 1/2″ cap is the one most often used on basin and bath waste pipe. Measure the outside of the pipe if you are not sure, because old metal waste can differ from modern plastic.