A friend has made a bedroom in a small cellar which has limited
ventallation, and its started to get damp. She's often away and wants
to leave something down there to ventallate it.

Its difficult to put a dehumidifier down there as there's no where for
hte draining pipe to go and they don't want to keep carrying water
out.

If she puts a ventallation fan in, it'll cost a lot in heating as hot
air is blown out of the house.

Is there any way she can get air into there, either with a pipe that
blows or sucks air, or some other contraption that removes humidity
but will take the water out.

The cellar is only accepsable by stairs, but does have a ventallation
grill.


thanks

On 28 Sep, 08:30, t8769 wrote:
A friend has made a bedroom in a small cellar which has limited
ventallation, and its started to get damp. She's often away and wants
to leave something down there to ventallate it.

Its difficult to put a dehumidifier down there as there's no where for
hte draining pipe to go and they don't want to keep carrying water
out.

If she puts a ventallation fan in, it'll cost a lot in heating as hot
air is blown out of the house.

Is there any way she can get air into there, either with a pipe that
blows or sucks air, or some other contraption that removes humidity
but will take the water out.

The cellar is only accepsable by stairs, but does have a ventallation
grill.

thanks

One option is to use a "heat recovery ventilator". This is basically
an extraction fan with a heat exchanger which warms the incoming air
so reducing the heat loss. If you google it you'll get lots of options
of various sizes and controls. You can for example get them with a
humidistat control to only turn on when it get's too damp.

I could put some links, but once you know what to look for it's pretty
straightforward to find something. You do need a slightly bigger hole
than for a standard ventilation fan but not much.

Fash

t8769 wrote:

A friend has made a bedroom in a small cellar which has limited
ventallation, and its started to get damp. She's often away and wants
to leave something down there to ventallate it.

Its difficult to put a dehumidifier down there as there's no where for
hte draining pipe to go and they don't want to keep carrying water
out.

If she puts a ventallation fan in, it'll cost a lot in heating as hot
air is blown out of the house.

Is there any way she can get air into there, either with a pipe that
blows or sucks air, or some other contraption that removes humidity
but will take the water out.

The cellar is only accepsable by stairs, but does have a ventallation
grill.


thanks

Dehumidifier works out cheaper all said. You can add a condensate
pump if you want to route the water up a floor. Carrying a gallon of
water out once or twice a week is no big deal really.

Its also poss to use a fan to exchange air betwen celler and ground
floor, and put your dehunid on the ground floor, but this is less
effective and allows little possibility of differing heating.


NT

wrote:
t8769 wrote:

A friend has made a bedroom in a small cellar which has limited
ventallation, and its started to get damp. She's often away and wants
to leave something down there to ventallate it.

Its difficult to put a dehumidifier down there as there's no where for
hte draining pipe to go and they don't want to keep carrying water
out.

If she puts a ventallation fan in, it'll cost a lot in heating as hot
air is blown out of the house.

Is there any way she can get air into there, either with a pipe that
blows or sucks air, or some other contraption that removes humidity
but will take the water out.

The cellar is only accepsable by stairs, but does have a ventallation
grill.


thanks

Dehumidifier works out cheaper all said. You can add a condensate
pump if you want to route the water up a floor. Carrying a gallon of
water out once or twice a week is no big deal really.

Its also poss to use a fan to exchange air betwen celler and ground
floor, and put your dehunid on the ground floor, but this is less
effective and allows little possibility of differing heating.


NT


With ventilation I'd say a DH is a complete waste of time. You will
simply be sucking air in from the world at large. Reassuring when you
see how much water it generates, but ultimately pointless. A sealed
space is a different matter.

Stuart Noble wrote:
wrote:
t8769 wrote:

A friend has made a bedroom in a small cellar which has limited
ventallation, and its started to get damp. She's often away and wants
to leave something down there to ventallate it.

Its difficult to put a dehumidifier down there as there's no where for
hte draining pipe to go and they don't want to keep carrying water
out.

If she puts a ventallation fan in, it'll cost a lot in heating as hot
air is blown out of the house.

Is there any way she can get air into there, either with a pipe that
blows or sucks air, or some other contraption that removes humidity
but will take the water out.

The cellar is only accepsable by stairs, but does have a ventallation
grill.


thanks

Dehumidifier works out cheaper all said. You can add a condensate
pump if you want to route the water up a floor. Carrying a gallon of
water out once or twice a week is no big deal really.

Its also poss to use a fan to exchange air betwen celler and ground
floor, and put your dehunid on the ground floor, but this is less
effective and allows little possibility of differing heating.


NT


With ventilation I'd say a DH is a complete waste of time. You will
simply be sucking air in from the world at large. Reassuring when you
see how much water it generates, but ultimately pointless. A sealed
space is a different matter.

Venting to the rest of the house merely moves the damp from one
location to another, where it is extracted. There is no reason to seal
a room up to dehumid it.


NT

On 28 Sep, 08:30, t8769 wrote:
A friend has made a bedroom in a small cellar which has limited
ventallation, and its started to get damp. She's often away and wants
to leave something down there to ventallate it.

Its difficult to put a dehumidifier down there as there's no where for
hte draining pipe to go and they don't want to keep carrying water
out.

If she puts a ventallation fan in, it'll cost a lot in heating as hot
air is blown out of the house.

Is there any way she can get air into there, either with a pipe that
blows or sucks air, or some other contraption that removes humidity
but will take the water out.

The cellar is only accepsable by stairs, but does have a ventallation
grill.

thanks

Dear T 8769
Your friend was ill-advised to do this without considering all the
necessary factors in the first place and if it is a legally habitable
room (a bedroom) it must, surely, have a window? Absent a window I may
be wrong but I think it will not conform to Building Regs and she puts
herself at risk should she put any guests or any other person than
herslef in such a location should they come to harm.
That said I think she needs to determine if the dampmess is as a
result of failure of the tanking or condensation now that it is
tanked. If the former then my advice is to start again or just use it
for storage. If the latter then all the normal condensation controls
can be applied eg insulate the walls internally to keep the dew point
up, control the water vapour entering, (a bit difficult if someone is
sleeping!) and providing ventilation. How to do the ventilation all
depends on the layout but in most houses with cellars there are
suspended timber floors (ok not all!) and if there are suspended
floors there are two routes (at least) to ventilate to the exterior, I
would introduce one at the front and one at the back (or sides -
whatever) such as to establish a flow thru from the outside just as
one would with a window. I would have the vents controllable with,
say, trickle vent capacity and this together with heating should make
the place less prone to condensation particularly if someone is
sleeping in it.
A dehumididifer would be a complete waste of time unless you were
able to seal the area from other wet air and would not be appropriate
for anything other than a one-off drying operation say after a flood.
(ok you could put one in on a humidistat but that is curing the
symptom not the problem).
Chris

wrote:

A dehumididifer would be a complete waste of time unless you were
able to seal the area from other wet air and would not be appropriate
for anything other than a one-off drying operation say after a flood.
(ok you could put one in on a humidistat but that is curing the
symptom not the problem).

Sounds like you've not done it. Its very effective.


NT

wrote:
wrote:

A dehumididifer would be a complete waste of time unless you were
able to seal the area from other wet air and would not be appropriate
for anything other than a one-off drying operation say after a flood.
(ok you could put one in on a humidistat but that is curing the
symptom not the problem).

Sounds like you've not done it. Its very effective.


NT

How can a dehumidifier be effective in this situation?

Stuart and Chris have made the point that a dehumidifier would need to
be in a sealed room to be effective and this is fact.

Unless you have a way of knowing where the individual water molecules in
your house originated from and have a way of identifying said molecules
and, then somehow, cleverly diverting those nasty extra water molecules
elsewhere so that they went nowhere near your dehumidifier?

Dehumidifiers have their place but as Chris has said you must realise
that they are not a cure and that their use will only help drying out
and then only if they are used correctly.

Steve

Steve wrote:
wrote:
wrote:

A dehumididifer would be a complete waste of time unless you were
able to seal the area from other wet air and would not be appropriate
for anything other than a one-off drying operation say after a flood.
(ok you could put one in on a humidistat but that is curing the
symptom not the problem).

Sounds like you've not done it. Its very effective.

How can a dehumidifier be effective in this situation?

Stuart and Chris have made the point that a dehumidifier would need to
be in a sealed room to be effective and this is fact.

I'm sorry but its not, and I know that from years of using them.


Unless you have a way of knowing where the individual water molecules in
your house originated from and have a way of identifying said molecules
and, then somehow, cleverly diverting those nasty extra water molecules
elsewhere so that they went nowhere near your dehumidifier?

huh?


Dehumidifiers have their place but as Chris has said you must realise
that they are not a cure

It depends. In some cases theyre all the treatment thats needed,
and in some not so. For cellars theyre cheaper and more energy
efficient than unnecessary ventilation, and often all that's required
to make a place healthy.

All habitable rooms should have some ventilation, so if the cellar has
none it will need it, but if its still damp, a dh is a simple
solution.


and that their use will only help drying out
and then only if they are used correctly.

Steve

You can use them for one off events such as flooding, or for ongoing
control of excess damp, or for other purposes such as drying
clothes etc.


NT

On 30 Sep, 00:14, wrote:
Steve wrote:
wrote:
wrote:
A dehumididifer would be a complete waste of time unless you were
able to seal the area from other wet air and would not be appropriate
for anything other than a one-off drying operation say after a flood.
(ok you could put one in on a humidistat but that is curing the
symptom not the problem).

Sounds like you've not done it. Its very effective.
How can a dehumidifier be effective in this situation?

Stuart and Chris have made the point that a dehumidifier would need to
be in a sealed room to be effective and this is fact.

I'm sorry but its not, and I know that from years of using them.

Unless you have a way of knowing where the individual water molecules in
your house originated from and have a way of identifying said molecules
and, then somehow, cleverly diverting those nasty extra water molecules
elsewhere so that they went nowhere near your dehumidifier?

huh?

Dehumidifiers have their place but as Chris has said you must realise
that they are not a cure

It depends. In some cases theyre all the treatment thats needed,
and in some not so. For cellars theyre cheaper and more energy
efficient than unnecessary ventilation, and often all that's required
to make a place healthy.

All habitable rooms should have some ventilation, so if the cellar has
none it will need it, but if its still damp, a dh is a simple
solution.

and that their use will only help drying out
and then only if they are used correctly.

Steve

You can use them for one off events such as flooding, or for ongoing
control of excess damp, or for other purposes such as drying
clothes etc.

NT

Dear NT
Years of use, per se, do not change the laws of physics. Think about
the process and you will see that your experience is telling you
something that is not what you have deduced it is. Here we have a
cellar - which is wet either from condensation or failure of tanking.
For the purposes of our discussion it matters not which. The cellar
has access to the rest of the house ( a door) and some minimal
ventilation (see the original post). Water molecules travel in air at
a considerable speed and consider the findings of Dalton with respect
to vapour pressure. Install a dehumidifier in a room which has open
windows or ANY access to open air and you are not dehumidifying that
room but the rest of the world. Not surprising that it fills up the
machine with lots of water.
As part of my professional work I have been responsible for designing
dehumidification for flooded (be it post Fire Brigade, loft tank
failure, roof failure, storm damage or whatever) buildings from Grade
1 listed properties of national importance to 3 up 2 down terraces in
Balham. The proceedure is to install the deumidifier in the area
concerned and close all windows and doors supplementing if necessary
with duct tape or polythene (if leaky as many old buildings are)
introducing (if in winter) electrical for remote source heat (dry
heat without use paraffin burners etc) humidistats, RH measurment
apparatus and most importantly to record the volume of water and
produce a graph v time to measure progress.
Absent a significant reduction in the source of water VAPOUR from
sources external to the cellar all you are doing is collecting water
from the environment as well as some from the cellar and not putting
the drying force where it is required - the walls of the cellar. Hope
this evidential approach to the discussion results in acceptance or an
evidential-based counter argument...
Chris

wrote:
On 30 Sep, 00:14, wrote:
Steve wrote:
wrote:
wrote:

A dehumididifer would be a complete waste of time unless you were
able to seal the area from other wet air and would not be appropriate
for anything other than a one-off drying operation say after a flood.
(ok you could put one in on a humidistat but that is curing the
symptom not the problem).

Sounds like you've not done it. Its very effective.
How can a dehumidifier be effective in this situation?

Stuart and Chris have made the point that a dehumidifier would need to
be in a sealed room to be effective and this is fact.

I'm sorry but its not, and I know that from years of using them.

Unless you have a way of knowing where the individual water molecules in
your house originated from and have a way of identifying said molecules
and, then somehow, cleverly diverting those nasty extra water molecules
elsewhere so that they went nowhere near your dehumidifier?

huh?

Dehumidifiers have their place but as Chris has said you must realise
that they are not a cure

It depends. In some cases theyre all the treatment thats needed,
and in some not so. For cellars theyre cheaper and more energy
efficient than unnecessary ventilation, and often all that's required
to make a place healthy.

All habitable rooms should have some ventilation, so if the cellar has
none it will need it, but if its still damp, a dh is a simple
solution.

and that their use will only help drying out
and then only if they are used correctly.

Steve

You can use them for one off events such as flooding, or for ongoing
control of excess damp, or for other purposes such as drying
clothes etc.

NT

Dear NT
Years of use, per se, do not change the laws of physics. Think about
the process and you will see that your experience is telling you
something that is not what you have deduced it is. Here we have a
cellar - which is wet either from condensation or failure of tanking.
For the purposes of our discussion it matters not which. The cellar
has access to the rest of the house ( a door) and some minimal
ventilation (see the original post). Water molecules travel in air at
a considerable speed and consider the findings of Dalton with respect
to vapour pressure. Install a dehumidifier in a room which has open
windows or ANY access to open air and you are not dehumidifying that
room but the rest of the world. Not surprising that it fills up the
machine with lots of water.
As part of my professional work I have been responsible for designing
dehumidification for flooded (be it post Fire Brigade, loft tank
failure, roof failure, storm damage or whatever) buildings from Grade
1 listed properties of national importance to 3 up 2 down terraces in
Balham. The proceedure is to install the deumidifier in the area
concerned and close all windows and doors supplementing if necessary
with duct tape or polythene (if leaky as many old buildings are)
introducing (if in winter) electrical for remote source heat (dry
heat without use paraffin burners etc) humidistats, RH measurment
apparatus and most importantly to record the volume of water and
produce a graph v time to measure progress.
Absent a significant reduction in the source of water VAPOUR from
sources external to the cellar all you are doing is collecting water
from the environment as well as some from the cellar and not putting
the drying force where it is required - the walls of the cellar. Hope
this evidential approach to the discussion results in acceptance or an
evidential-based counter argument...
Chris

Evidence based... with normal ventilation if I ran the dh the room
stayed dry, if I didnt it got a real damp problem. Same was true
either way, vented or not.

2nd piece of evidence: RH levels vary through some houses, with a
damp area and the rest not. The existence of some air movement
between the differing areas doesnt change that. It reduces the
difference, but does not eliminate it.

Theory based... air entering from outside carries with it a certain
level of water vapour. The RH in the damp room is the result of an
equilibrium between vapour ingress or egress and water entry from
the cause of the dampness. Adding a dehumidifier will shift that
point, reduce RH and increase rate of evaporation.

If youre doing a dry-out after a big flood, you'll get there quicker
if
you seal it all up, as you can then produce a lower RH. You can
also measure water collected. If OTOH youre in a normal living
situation, you dont want to seal your house up, and the limited
normal level of ventilation doesnt usually prevent the RH being
lowered to a useful target by a dehumidifier. If you had the windows
wide open that would be pointless, but normal ventilation is within
the capability of a domestic size machine to keep Rh down in one
room, and the resulting water collection is not affected by a great
amount.


NT

Many thanks for the excellent suggestions and information.

The rest of the house is fine, the basement only slightly damp.

Perhaps the best solution would be to have a small fan that blows air
from the small basement room into the rest of the hose, thus getting
lots of ventallation into the room, but not blowing a lot of air out
of the house and costing lost of money for heating.

Its a bit late for tanking, and the damp isn't that bad.


Cheers

On 1 Oct, 11:56, t8769 wrote:
Many thanks for the excellent suggestions and information.

The rest of the house is fine, the basement only slightly damp.

Perhaps the best solution would be to have a small fan that blows air
from the small basement room into the rest of the hose, thus getting
lots of ventallation into the room, but not blowing a lot of air out
of the house and costing lost of money for heating.

Its a bit late for tanking, and the damp isn't that bad.

Cheers

Why not use a heat recovery ventilator to the outside. This way you
can increase the number of air changes and reduce humidity by bringing
in colder air from outside which holds less water. The 'heat recovery'
part means having a heat exchanger in the ventilator which warms the
outside air coming in using the inside air going out. Do a google
search to find suppliers.

Roughly speaking you can triple the ventilation rate without impacting
on the heating bill. You can use humidistat controls or timers or
whatever. I could put some links but I presume you can google for
yourself.

Regards,

Fash

Thanks for the info guys.

As it is only slightly damp, I have a feeling that a fan circulating
air to the rest of the house would probably do the trick, but
otherwise the heat recovery ventilator sounds ideal


Cheers

On 3 Oct, 00:34, t8769 wrote:
Thanks for the info guys.

As it is only slightly damp, I have a feeling that a fan circulating
air to the rest of the house would probably do the trick, but
otherwise the heat recovery ventilator sounds ideal

Cheers

Just visited a building which got flooded,
they put in a dehumidifier
but did it wrong,
the roof beams cracked and the ceiling sagged!

they are not happy bunnies

[g]