My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

On Mar 31, 12:30 pm, stuart noble wrote:
My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

put dye down the roof drains first?

Jim K

On Mar 31, 12:55*pm, Jim K wrote:
On Mar 31, 12:30 pm, stuart noble wrote:

My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

put dye down the roof drains first?

Jim K

Yes. that is the very first thing to do. You can bet this is not a
problem that existed from year one. Something has happened, leaking
drain could be it.

On 31/03/2011 18:00, harry wrote:
On Mar 31, 12:55 pm, Jim wrote:
On Mar 31, 12:30 pm, stuart wrote:

My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

put dye down the roof drains first?

Jim K

Yes. that is the very first thing to do. You can bet this is not a
problem that existed from year one. Something has happened, leaking
drain could be it.

In this case it *has* existed from year one. The cellar floods
periodically, as do all the adjoining houses, due solely to the water
table. It's been happening on and off since 1920, though it has
apparently got worse following major infrastructure work in the area.
Fortunately the floors are bone dry, being 6 feet above any standing
water with plenty of ventilation in between. So thanks for the advice
about tanking and pumps etc, but it's not really appropriate in this
instance.
Last time they all had 6" of water in their cellars a neighbour
installed a pump that ran continuously for a week. Needless to say it
made no difference, but when the level in the nearby lake dropped, the
cellars dried up.

On Mar 31, 6:56 pm, stuart noble wrote:
On 31/03/2011 18:00, harry wrote:



On Mar 31, 12:55 pm, Jim wrote:
On Mar 31, 12:30 pm, stuart wrote:

My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

put dye down the roof drains first?

Jim K

Yes. that is the very first thing to do. You can bet this is not a
problem that existed from year one. Something has happened, leaking
drain could be it.

In this case it *has* existed from year one. The cellar floods
periodically, as do all the adjoining houses, due solely to the water
table. It's been happening on and off since 1920, though it has
apparently got worse following major infrastructure work in the area.
Fortunately the floors are bone dry, being 6 feet above any standing
water with plenty of ventilation in between. So thanks for the advice
about tanking and pumps etc, but it's not really appropriate in this
instance.
Last time they all had 6" of water in their cellars a neighbour
installed a pump that ran continuously for a week. Needless to say it
made no difference, but when the level in the nearby lake dropped, the
cellars dried up.

time to fill it in by 7inches?

Jim K

On 31/03/2011 19:08, Jim K wrote:
On Mar 31, 6:56 pm, stuart wrote:
On 31/03/2011 18:00, harry wrote:



On Mar 31, 12:55 pm, Jim wrote:
On Mar 31, 12:30 pm, stuart wrote:

My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

put dye down the roof drains first?

Jim K

Yes. that is the very first thing to do. You can bet this is not a
problem that existed from year one. Something has happened, leaking
drain could be it.

In this case it *has* existed from year one. The cellar floods
periodically, as do all the adjoining houses, due solely to the water
table. It's been happening on and off since 1920, though it has
apparently got worse following major infrastructure work in the area.
Fortunately the floors are bone dry, being 6 feet above any standing
water with plenty of ventilation in between. So thanks for the advice
about tanking and pumps etc, but it's not really appropriate in this
instance.
Last time they all had 6" of water in their cellars a neighbour
installed a pump that ran continuously for a week. Needless to say it
made no difference, but when the level in the nearby lake dropped, the
cellars dried up.

time to fill it in by 7inches?

Jim K

Yeah, and walk with a stoop :-)
It occurs to me that if I dug a 6 foot hole in my garden, there might
well be 6" of water in the bottom most of the year, so I guess it
shouldn't be surprising to see it in a cellar. However, the name of this
particular road suggests that the area has a historical association with
flooding and maybe these cellars are spare capacity in the event of a
serious flood.

On Mar 31, 12:30*pm, stuart noble wrote:
My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

How about some ventilation in that cellar.

On 31/03/2011 14:07, wrote:
On Mar 31, 12:30 pm, stuart wrote:
My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

How about some ventilation in that cellar.

Plenty of that thanks. You can't fight the water table, which floods
every cellar in the road when it's high.

On Mar 31, 3:39 pm, stuart noble wrote:
On 31/03/2011 14:07, wrote:

On Mar 31, 12:30 pm, stuart wrote:
My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

How about some ventilation in that cellar.

Plenty of that thanks. You can't fight the water table, which floods
every cellar in the road when it's high.

wonder why they built them with cellars then?

Jim K

On Mar 31, 4:48*pm, Jim K wrote:

Plenty of that thanks. You can't fight the water table, which floods
every cellar in the road when it's high.

wonder why they built them with cellars then?

It's not unusual. 100 years ago, when they built them, they were dry.
50 years ago they were dry. Then they built a sodding great Tesco
alongside with a massive carpark and instant rainwater runoff. The
short term water table around the edge of this watershed then jumps up
by three feet and things that have never flooded before start to
flood.

In message
,
Andy Dingley writes
On Mar 31, 4:48*pm, Jim K wrote:

Plenty of that thanks. You can't fight the water table, which floods
every cellar in the road when it's high.

wonder why they built them with cellars then?

It's not unusual. 100 years ago, when they built them, they were dry.
50 years ago they were dry. Then they built a sodding great Tesco
alongside with a massive carpark and instant rainwater runoff. The
short term water table around the edge of this watershed then jumps up
by three feet and things that have never flooded before start to
flood.

Yup. We have a Victorian house in Cambs (not the Fens)with a brick built
cellar. It is a bit damp, mostly up through the floor (things stored
there are ok, as long as kept off the floor). It has flooded before, but
not in our time here (5 years), but a few times with the previous
owners. They left us the pump they used to pump it out. I know of other
houses nearby with the same situation. So it's obviously a general
change in the water table.

But we have a copy of the sale particulars from the 1960's, when having
a dry cellar was highlighted as selling point. so presumably by then
there was a change for some houses in the area.
--
Chris French

On Mar 31, 3:39*pm, stuart noble wrote:
On 31/03/2011 14:07, wrote:

On Mar 31, 12:30 pm, stuart *wrote:
My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

How about some ventilation in that cellar.

Plenty of that thanks. You can't fight the water table, which floods
every cellar in the road when it's high.

Hmm. You need to get that sorted by tanking/other water proofingdrain
and/or a sump and pump in the cellar.
It's not a problem you should ignore. There are solutions but none of
them are cheap.

In message
,
harry writes
On Mar 31, 3:39*pm, stuart noble wrote:
On 31/03/2011 14:07, wrote:

On Mar 31, 12:30 pm, stuart *wrote:
My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

How about some ventilation in that cellar.

Plenty of that thanks. You can't fight the water table, which floods
every cellar in the road when it's high.

Hmm. You need to get that sorted by tanking/other water proofingdrain
and/or a sump and pump in the cellar.
It's not a problem you should ignore. There are solutions but none of
them are cheap.

Unless he wants to use the cellar then there seems no need to do such
things. As long as the ventilation is sufficient of course
--
Chris French

On Mar 31, 2:07*pm, " wrote:
On Mar 31, 12:30*pm, stuart noble wrote:

My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

How about some ventilation in that cellar.

Yes, that's correct. Plus some insulation beneath the floorboards.
You need to check the joists ends for rot too if it's that bad.

On Mar 31, 12:30*pm, stuart noble wrote:
My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

The only question I'd ask is whether there's a risk of condensation
forming on the top of the plastic.


NT

On 31/03/2011 18:10, Tabby wrote:
On Mar 31, 12:30 pm, stuart wrote:
My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

The only question I'd ask is whether there's a risk of condensation
forming on the top of the plastic.


NT

AIUI there should be no cold surface on the upper side of the
insulation, and the 4" gap between it and the boards will be ventilated
from above, but I'm prepared to be corrected about that

[Default] On Thu, 31 Mar 2011 19:12:05 +0100, a certain chimpanzee,
stuart noble , randomly hit the keyboard
and wrote:

AIUI there should be no cold surface on the upper side of the
insulation, and the 4" gap between it and the boards will be ventilated
from above, but I'm prepared to be corrected about that

You would be trapping the warm moist air from the house in the space
between the joists. There will be an increased risk of condensation on
the upper surface of the bubblewrap (and at the lower surface of the
joists) if it doesn't provide sufficient insulation.

Either underdraw the whole floor with Celotex or a multifoil (Tri-Iso)
which will ensure that the air trapped there is close to room
temperature. Otherwise, mineral fibre insulation (Rockwool) between
the joists and, to stop the musty smell, increase the ventilation to
the cellar & seal up the gaps between the floorboards.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have I strayed"?

On 31/03/2011 20:57, Hugo Nebula wrote:
[Default] On Thu, 31 Mar 2011 19:12:05 +0100, a certain chimpanzee,
stuart , randomly hit the keyboard
and wrote:

AIUI there should be no cold surface on the upper side of the
insulation, and the 4" gap between it and the boards will be ventilated
from above, but I'm prepared to be corrected about that

You would be trapping the warm moist air from the house in the space
between the joists. There will be an increased risk of condensation on
the upper surface of the bubblewrap (and at the lower surface of the
joists) if it doesn't provide sufficient insulation.

Either underdraw the whole floor with Celotex or a multifoil (Tri-Iso)
which will ensure that the air trapped there is close to room
temperature. Otherwise, mineral fibre insulation (Rockwool) between
the joists and, to stop the musty smell, increase the ventilation to
the cellar& seal up the gaps between the floorboards.

Thanks. I'll look into the multifoil products, but at first glance they
seem a bit pricey for the ground floor where heat loss isn't the main issue.

In article , stuart noble
writes
On 31/03/2011 20:57, Hugo Nebula wrote:
[Default] On Thu, 31 Mar 2011 19:12:05 +0100, a certain chimpanzee,
stuart , randomly hit the keyboard
and wrote:

AIUI there should be no cold surface on the upper side of the
insulation, and the 4" gap between it and the boards will be ventilated
from above, but I'm prepared to be corrected about that

You would be trapping the warm moist air from the house in the space
between the joists. There will be an increased risk of condensation on
the upper surface of the bubblewrap (and at the lower surface of the
joists) if it doesn't provide sufficient insulation.

Either underdraw the whole floor with Celotex or a multifoil (Tri-Iso)
which will ensure that the air trapped there is close to room
temperature. Otherwise, mineral fibre insulation (Rockwool) between
the joists and, to stop the musty smell, increase the ventilation to
the cellar& seal up the gaps between the floorboards.

Thanks. I'll look into the multifoil products, but at first glance they
seem a bit pricey for the ground floor where heat loss isn't the main issue.

Absolute junk IMNSHO, stick with the rockwool or celotex in intimate
contact with the boards. The gap under the skirting is a common place
for draughts and so smells to permeate. I've used a low modulus sealant
to seal off mine, an acrylic one if you want to paint over it (not
caulk, it's not flexible enough). If they have carpet then you could
just lift it, board out with hardboard, duct tape the joints and seal
the skirting gap.
--
fred
FIVE TV's superbright logo - not the DOG's, it's ********

On Mar 31, 7:12*pm, stuart noble wrote:
On 31/03/2011 18:10, Tabby wrote:



On Mar 31, 12:30 pm, stuart *wrote:
My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

The only question I'd ask is whether there's a risk of condensation
forming on the top of the plastic.

NT

AIUI there should be no cold surface on the upper side of the
insulation, and the 4" gap between it and the boards will be ventilated
from above, but I'm prepared to be corrected about that


A single layer of bubblewrap struggles to qualify as insulation, so I
do think condensation would be a risk. Imagine a nice warm summer day,
with a damp wet cellar, its asking for condensation from the warm air.
If you kept the wrap spaced off the joists and provided little drain
holes, that would work, Hugo's suggestion of real insulation sounds
better though.


NT

On 31/03/2011 21:30, Tabby wrote:
On Mar 31, 7:12 pm, stuart wrote:
On 31/03/2011 18:10, Tabby wrote:



On Mar 31, 12:30 pm, stuart wrote:
My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

The only question I'd ask is whether there's a risk of condensation
forming on the top of the plastic.

NT

AIUI there should be no cold surface on the upper side of the
insulation, and the 4" gap between it and the boards will be ventilated
from above, but I'm prepared to be corrected about that


A single layer of bubblewrap struggles to qualify as insulation, so I
do think condensation would be a risk. Imagine a nice warm summer day,
with a damp wet cellar, its asking for condensation from the warm air.
If you kept the wrap spaced off the joists and provided little drain
holes, that would work, Hugo's suggestion of real insulation sounds
better though.


NT

I don't want to reduce the height in the cellar so it sounds like I'll
have to go between the joists with something. I don't think the budget
will stretch to Celotex though

On Apr 1, 8:56*am, stuart noble wrote:
On 31/03/2011 21:30, Tabby wrote:



On Mar 31, 7:12 pm, stuart *wrote:
On 31/03/2011 18:10, Tabby wrote:

On Mar 31, 12:30 pm, stuart * *wrote:
My son's house has a large cellar which, due to the local water table,
is often wetter than might be expected. With bare boards on the ground
floor there is inevitably a musty smell coming up when it rains, so I'm
looking for a way to block the gaps between the boards. I've thought
about gap seal type products but, given the good access from below,
that doesn't seem to be the best option. Celotex between the joists
would be ideal but, as heat loss isn't the main issue, I'm wondering
about stapling foil/bubblewrap to the underside of the joists. I'm
assuming foil tape would be ok for the long edges, but is it likely to
sag and blow about over time? Anyone done anything similar?

The only question I'd ask is whether there's a risk of condensation
forming on the top of the plastic.

NT

AIUI there should be no cold surface on the upper side of the
insulation, and the 4" gap between it and the boards will be ventilated
from above, but I'm prepared to be corrected about that

A single layer of bubblewrap struggles to qualify as insulation, so I
do think condensation would be a risk. Imagine a nice warm summer day,
with a damp wet cellar, its asking for condensation from the warm air.
If you kept the wrap spaced off the joists and provided little drain
holes, that would work, Hugo's suggestion of real insulation sounds
better though.

NT

I don't want to reduce the height in the cellar so it sounds like I'll
have to go between the joists with something. I don't think the budget
will stretch to Celotex though

You cant afford to lose half an inch? I dont see how youre going to
put insulation between the joists, plus a membrane, and eliminate risk
of condensation. It takes very little insulation under it all to
prevent condensation.


NT