Sealing service ducts into house

[lizzie]

I have several ducts from outside through the MBC slab and up into the plant room. These are just black corrugated pipe nothing special.  All the services run in these into the plant room.

 

These ducts have not been sealed they are still open inside the house and out in the back alley...(ratfest waiting to happen, we have a livery next to us so plenty of furry things about).The ducts outside have been covered in gravel, I asked how they had been sealed before covering with gravel and I was told gravel just went down on top of open ducts. I had been assured all ducts were going to be sealed before BC sign off but it never happened and now builders have headed off at speed to the next pot of gold at the end of another rainbow I am left with open ducts amongst a myriad of other small items not finished off.  

 

No grommets were put on pipes before service cables pulled so whatever is done will have to be not only durable but flexible to be able to fill voids.  Expanding foam perhaps? Will I need steel wool or something too to stop ratty getting in? Do I need to allow for opening ducts again in the future?

 

All suggestions gratefully received.  Thankfully I still have my trusty carpenter to help me as I am no good at all at this sort of thing.

[CC45]

Weve got this to some extent - light fittings pass through the exterior wall and into the house etc.  If small I was just going to seal them with silicone - well forced into the hole, if bigger I guess expanding foam first.  A few on here know which silicone sealants are safe to use with electric cable - I cant remember now, but a search on here might reveal the answer.  For rats a few seem to have used scouring pads.

 

Finishing details seem to take a long time.

 

Let us know what you do in the end.

[Cpd]

Stainless steel scouring pads / stainless steel wire wool could be stuffed in and around the pipes at both ends, i then squirted some expanding foam into the stuffed in wire wool to secure it and prevent drafts, it also will prolongs the life of the wire wool as its not top rated A2 stainless and will degrade over time i expect. Worked for me against mice, could see where they had a go at the expanding foam, hit the wool and gave up. 

[Onoff]

Rockwool FIREPRO is an intumescent sealant and Soudal FR an intumescent foam. Both specify in their bumpf for cable penetrations. 

 

Ref the steel wool use stainless steel.

[nod]

4 hours ago, lizzie said:

I have several ducts from outside through the MBC slab and up into the plant room. These are just black corrugated pipe nothing special.  All the services run in these into the plant room.

 

These ducts have not been sealed they are still open inside the house and out in the back alley...(ratfest waiting to happen, we have a livery next to us so plenty of furry things about).The ducts outside have been covered in gravel, I asked how they had been sealed before covering with gravel and I was told gravel just went down on top of open ducts. I had been assured all ducts were going to be sealed before BC sign off but it never happened and now builders have headed off at speed to the next pot of gold at the end of another rainbow I am left with open ducts amongst a myriad of other small items not finished off.  

 

No grommets were put on pipes before service cables pulled so whatever is done will have to be not only durable but flexible to be able to fill voids.  Expanding foam perhaps? Will I need steel wool or something too to stop ratty getting in? Do I need to allow for opening ducts again in the future?

 

All suggestions gratefully received.  Thankfully I still have my trusty carpenter to help me as I am no good at all at this sort of thing.

Not sure if it’s correct But we have the same issue with a wooded area and a stream running along the side of the house

i put tape around the ductings then empted a strong mirror mix over and under them

Not pretty But effective Then covered with gravel 

[Onoff]

Crushed/broken glass in the mix or held in place by foam is supposed to work. A lot of the old shacks down here had concrete floors laid on a bed of broken glass. I wouldn't fancy any sharp edges on cables though.

[Jeremy Harris]

I solved this with rolled up balls of chicken wire, with a bit of heavy gauge fencing wire threaded through the centre and twisted back in itself.  What you do it feed the pipes, cables etc through the ducts, then poke the ball of chicken wire down, with the heavy gauge wire poking up.  Then use expanding foam to seal the duct on top of the chicken wire, again with the heavy gauge wire poking out.  Do this at both ends of every duct, although there's no need for foam on the outside ends. 

 

The ball of chicken wire should act as a pretty effective rodent barrier.  If you ever need to run another cable or pipe in the duct, you can just pull the ball of chicken wire out using the heavy gauge fencing wire as a handle.  The foam seals the ducts up reasonably well, but doesn't adhere that well to the inside of the duct surface, so can be pulled out (I've already had to do this to one to run another cable in).  I finished off over the foam with some airtightness tape inside the house, but I don't think it's really needed, the foam does a good enough job.

[lizzie]

Thanks for all the tipsthats fantastic. I will investigate the options suggested and let you know how we end up

Superstars all of you!