Hi,

I'll be doing some work on the kitchen in the near future, and having
moved things around to measure them I have found that the gas pipe to
the cooker is in very poor condition - it is buried under the concrete
floor with seemingly no protection and at the point where it exits the
floor it is very green and corroded looking. I am assuming that I have
no other option but to replace it (tell me if I'm wrong to save me some
work!) Am also planning to replace cooker with gas hob/electric oven.

While I'm at it, I'm going to upgrade the pipework to the boiler to 22mm
as it is currently only 15mm.

The gas supply and meter come in to the front of the house in a cupboard
in the living room. The kitchen is in a single storey extension at the
back. My options are as follows:

1) Take 22mm pipe under living room floor (this isn't concrete, only
the extension is) from meter, up through the cupboard where the boiler
is, T off to boiler with short lenght of 15mm. Carry on up the cupboard
with 15mm to under the floorboards on the landing. Take it accross the
landing, through back bedroom and down into dining room where it will be
boxed in vertically until going through the wall into the kitchen roof
space. Then down through the ceiling to below hob height, across the
wall behind the units and into hob.

My main question relating to this option is what I am supposed to do
when running the pipe through the wall into the extension. I know that
you are supposed to sleeve the pipe and only seal it at one end - but
which end? If I seal it at the house end and there is a leak it will
spill into the roof space of the extension which is enclosed so would
allow gas to build up - if I seal it on the extension side then it will
build up in the boxing in on the house side. Any ideas what would be
best?

2) Dig up channel in kitchen floor to replace the current run of pipe.

Not sure if this is easier or harder - I'm assuming my trusty SDS with a
chisel bit would make fairly light work of digging up the channel
(probably cut the edges with an angle grinder) - but how do I go about
filling it or covering it afterwards? I would preferably cover it with
wood as opposed to refilling it to aid future access.

Any adivce/ideas/criticisms on the above would be greatly appreciated.

Thanks,
Richard

"Richard Conway" wrote in message
...
Hi,

I'll be doing some work on the kitchen in the near future, and having
moved things around to measure them I have found that the gas pipe to the
cooker is in very poor condition - it is buried under the concrete floor
with seemingly no protection and at the point where it exits the floor it
is very green and corroded looking. I am assuming that I have no other
option but to replace it (tell me if I'm wrong to save me some work!) Am
also planning to replace cooker with gas hob/electric oven.

While I'm at it, I'm going to upgrade the pipework to the boiler to 22mm
as it is currently only 15mm.

The gas supply and meter come in to the front of the house in a cupboard
in the living room. The kitchen is in a single storey extension at the
back. My options are as follows:

1) Take 22mm pipe under living room floor (this isn't concrete, only the
extension is) from meter, up through the cupboard where the boiler is, T
off to boiler with short lenght of 15mm. Carry on up the cupboard with
15mm to under the floorboards on the landing. Take it accross the
landing, through back bedroom and down into dining room where it will be
boxed in vertically until going through the wall into the kitchen roof
space. Then down through the ceiling to below hob height, across the wall
behind the units and into hob.

My main question relating to this option is what I am supposed to do when
running the pipe through the wall into the extension. I know that you are
supposed to sleeve the pipe and only seal it at one end - but which end?
If I seal it at the house end and there is a leak it will spill into the
roof space of the extension which is enclosed so would allow gas to build
up - if I seal it on the extension side then it will build up in the
boxing in on the house side. Any ideas what would be best?

I had a vaguely similar problem. I can't quote the regs, but had to run some
gas pipe in a stud wall cavity. I eventually settled for running the pipe in
some
solvent weld plastic gutter pipe, after asking around a bit. This allowed
the pipe to enter an unvented
area, but still itself be vented by the ends of the gutter pipe, which
emerged
into the room ( the gas pipe went into the studding for a bit then
reemerged ).

You know that the main reason behind the gas pipe needing a
plastic sleeve when it goes through a cavity wall is that the consequences
of
a build up in the cavity, if ignited, could lead to collapse of that wall. I
imagine
that a leak into your (unvented?) kitchen extension roofspace would have bad
conortations, if not as bad as the cavity wall. The boxed in section seems
to
me to be the least worst place for a gas leak, being non-structural and with
a small
enclosed volume. The other reason for sleeving a pipe as it goes through a
wall is
that it is most vulnerable there, to scraping and distortion in case of
movement of
the house due to settling or seasonal heave or thermal expansion etc.

I would put a couple of uncloseable louvre vents in the boxed in section,
one top, one bottom.
I would vent the pipe sleeving into the boxed section, and seal the end of
the sleeve
going to the wall at the kitchen roof space end. This leaves the sealed
volume of the roof space
as the one place where a leak could build up, although the pipe will not be
particularly
vulnerable there. After all, if it is permissible to run a pipe under the
floorboards, that
gives the same sort of problem.

A belt and braces measure would be to sleeve the gas pipe where it enters
the
roof space with 4" diameter gutter pipe ( else you can't assemble things )
and seal that gutter pipe where the gas pipe + wall sleeve emerges into the
roofspace, then have the gas pipe and gutter pipe sleeving emerge through
the
kitchen roof. Any gas leak then has a small volume path to a ventilated
area.

I'm sure this is OTT but will at least give you a warm fuzzy feeling! I
don't know the
regs as they pertain to unventilated roof spaces.

2) Dig up channel in kitchen floor to replace the current run of pipe.

Not sure if this is easier or harder - I'm assuming my trusty SDS with a
chisel bit would make fairly light work of digging up the channel
(probably cut the edges with an angle grinder) - but how do I go about
filling it or covering it afterwards? I would preferably cover it with
wood as opposed to refilling it to aid future access.

Any adivce/ideas/criticisms on the above would be greatly appreciated.

Thanks,
Richard

Of course, don't recover with concrete as this corrodes the copper, unless
you
run it in plastic conduit or wrap it in denso tape. The wood sounds a good
idea,
you could seat the edges of the wood on a little mortar run along the edges
of the
channel you grind/chisel, that way it'll sit perfectly. DYOR.

I'm sure others on this NG will have suggestions.

Andy