Cover for old 4" soil pipe

RomfordNavy

Looking for a cap to cover the upright soil pipe to stop the rats from getting out: this passes through the roof and vents from the toilet outlet.  It appears to be 4" cast pipe but most of the fittings I find are 110mm which I presume will not fit.

WIAWSNB

Are you saying they are climbing up and out the top?! 😲 
There must be lots of mesh-type pipe covers that would be suitable.
Do you know the exact diameter of this pipe?* And does it have a wider collar at the top?
You could even get a handful of chicken fence, and crush it into a ball large enough to be a tight fit inside the pipe, and tamp it down. Totally hidden.

* Wrap a strip of paper around it, and mark where it overlaps. Divide that circumference by pi. 

RomfordNavy

Just measured it and outer diameter is 4.5" so from what I can establish the inner diameter is probably 3.83" (9.73cm).  Looking from the ground it does appear to have a collar of some sort at the top.

FreeBear

You can get couplings to go from cast iron pipe to modern plastic.

A vent pipe should not be blocked off, ever. You can get simple birdcage affairs that will clip over the top of C.I. pipe. Or with the use of an adaptor, a durgo valve could be fitted.

GDB2222

Can rats really climb up the inside of a vertical pipe? What stops them coming out of the toilet instead of climbing up to the top? 

WIAWSNB

Romford, have you actually seen rats come out this pipe?
If so, and you block their exit, where do you reckon they'll choose next?  😟 

bjorn_toby_wilde

I think you may be confusing the purpose of the soil vent terminals.  They’re usually fitted to prevent birds nesting in the top of the pipe and blocking air ingress. If the pipe was blocked at that point, flushing toilets would create a negative pressure which would empty out other traps on the same pipe run.

As @Freebear said, cast iron is 4” so you’d need a cast iron to 110 adapter then a 110 vent terminal should fit into the top of that. Don’t push anything down inside as you’ll just be helping the birds in their efforts.

grumpy_codger

FreeBear said:

...Or with the use of an adaptor, a durgo valve could be fitted.

AFAIK, most valves aren't recommended for outside use, but there is some brand that can be used.

RomfordNavy

GDB2222 said:

Can rats really climb up the inside of a vertical pipe? What stops them coming out of the toilet instead of climbing up to the top? 

Presumably the water.

RomfordNavy

FreeBear said:

You can get couplings to go from cast iron pipe to modern plastic.

A vent pipe should not be blocked off, ever. You can get simple birdcage affairs that will clip over the top of C.I. pipe. Or with the use of an adaptor, a durgo valve could be fitted.

Yep, looking for a cover of some sort, not a sealed cap.  Should have been clearer.

RomfordNavy

WIAWSNB said:

Romford, have you actually seen rats come out this pipe?
If so, and you block their exit, where do you reckon they'll choose next?  😟 

Well they are getting out somewhere around that area I can hear them at night, and can't see any other holes they could get out.  Have seen about six of these buggers in a group ripping rubish bags apart in the from garden, unbelievably one was the size of a cat, luckily it soon ran away when it saw me.