Sealing main water feed inside kitchen - Now with images !!!

[TonyWarrington]

The main water supply to my property is fed under/into kitchen cabinets and is housed in what looks like a 6" dia. plastic soil pipe. By the rubble that is left around it it looks like the builder cut through the concrete floor to lay this after the floor was laid!

I would like to seal the main water feed housed in the plastic pipe -mainly to stop possible ant invasion etc.

I have been thinking about either using expanding foam to seal the water pipe into the soil pipe or capping the top and using silicone sealant.

Is there any reason why this cannot be done or are there any alternatives?

 

[Expertboy]

Expanding foam should be ok.

 

[TonyWarrington]

Expertboy, thanks for the reply

I know that I am a sad person but as I could not see into the space took some pics (well its Sunday and raining what else to do )

View media item 4278After a large amount of building rubble removed

View media item 4277This is what I am intending to seal with expanding foam

View media item 4279The hole around the pipe - I can easily get my hand in! Not sure about the foam already there - was this sprayed in after or part of DPC?

 

[Steve69the69Gas]

Thats foam.

 

[TonyWarrington]

Steve69the69Gas, thanks - my terminology wrong (again!!)

If understand correctly a damp proof membrane would be laid first and then rigid insulation (Foam ?) is placed and the concrete slab is poured over the foam and d.p.m finally screed is applied. Can only assume my house built in similar way.

The foam seems very solidly attached therefore had thought that it might have been sprayed in - now I am of the opinion that it is probably part of the original rigid insulation laid over the DPM and has just got wedged in.

 

[rssteve]

does foam not damage the water pipe? i now it dosn;t do any good to pvc cables

 

[ChrisR]

What does it do to pvc cables ??

It's frequently used for pipes and I haven't heard of a problem

 

[lagunaglen]

The expanding foam will give any rats who get down that pipe a snack before they come into your nice warm well stocked kitchen.

 

[TonyWarrington]

Bloody Hell lagunaglen, are you trying to give me nightmares

Just read your post before going to bed. Realising that the pipe is open and now with the plinth removed kitchen is also open. Have now stuffed the opening with towels as a temporary measure and will wear bicycle clips to bed :

rssteve, think I will check with manufacturer about possible damage to water and elecs

 

[doitall]

I have seen dozens filled with expanding foam, But I have also heard a couple of rumors lately that it taints the water

TBH I can't see it would notice with running water.

 

[Kes]

The (soil) pipe is open? Isn't the other end 750 mm+ underground, so there would only be an invasion of deep tunnelling rats, or possibly curious moles?

How would expanding foam taint the water? Can its tainting molecules pass through the mdpe pipe walls?

 

[muggles]

I've heard that the chemicals in some expanding foams can attack the plastic pipe, although I've never seen any evidence for this. As for it tainting the water, I suppose it could creep through the MDPE, but I think it's unlikely.

Handy tip: Leave a plate of cat food by the pipe in the kitchen. It'll refresh the moles after a hard day's tunnelling into your house

 

[TonyWarrington]

FWIW did a little research i.e. email to manufacturer and googling re possible issues using foam with water pipes and electric cable.

Looks like the problem for electric cables is with polystyrene thermal insulation
Quote Voltimum -Only polystyrene thermal insulation is of serious concern for PVC sheathed cables. In general it is not required to place PVC sheathed cables in separate conduit if passed through polyurethane or polyisocyanurate thermal insulation. The thermal insulation polymers are different and do not have residual chemicals present that are found in polystyrene thermal insulation.

Not quite as clear cut with MDPE pipe! I emailed Polycell and got reply:
Normal Polycell Expanding foam is suitable for application around hot and cold water pipes. For electricity piping recommend using Polycell Trade Fire Retardant Expanding Foam

The data sheet for both products states
SUBSTRATES:
For all common building materials other than polyethylene, Teflon, silicon, oils and grease, mould and release agents.

AFAIK MDPE is manufactured using polyethylene! I suspect that the reference to non suitability with polyethylene may be due to poor adhesion rather than physical damage.