Appearance of Dampness in timber frame house

statty

Hi,
I have a timber-frame house. On the upstairs south side facing wall there is the appearance of mildew and dampness. This is also on the upstairs rear facing wall (west facing). I only see this on one of the west facing walls upstairs as the other walls are tiled. Although there is the appearance of mildew and dampness this is not wet. The walls are dry.

The house is well insulated both inside and outside so I do not know why this is happening. Does anyone have any ideas? Could it be something to do with ventilation. We open the windows regularly and have the vents open in the windows.

Any ideas of what is causing this or it can be avoided would be gratefully appreciated.

Thanks!

archtech

statty wrote: »

Hi,
I have a timber-frame house. On the upstairs south side facing wall there is the appearance of mildew and dampness. This is also on the upstairs rear facing wall (west facing). I only see this on one of the west facing walls upstairs as the other walls are tiled. Although there is the appearance of mildew and dampness this is not wet. The walls are dry.

The house is well insulated both inside and outside so I do not know why this is happening. Does anyone have any ideas? Could it be something to do with ventilation. We open the windows regularly and have the vents open in the windows.

Any ideas of what is causing this or it can be avoided would be gratefully appreciated.

Thanks!

You say the walks are well insulated both inside and outside ? Can you expand on this ?

statty

Well what I actually meant is the house is well insulated. As I said its timber frame so the actual timber frame is insulated and then there is internal insulation in the attic. Hope this helps - let me know if you need to expand more and ill find out the proper terms I should be using!

MicktheMan

Chances are that this is a combination of ventilation/heating/insulation(thermal bridging) but this generally shows first on the north and east side of the house.
When you say "south facing" do you mean the inside of the wall is south facing or the outside of the wall is south facing?

engineermike

Hi OP,
Its kind of difficult to ascertain the cause of the moisture with out assessment of the structure.
You mentioned the timber frame is insulated - is the insulant on the external facade ? ( EIFS - Externally insulated facade system) - known for failure in our climate.
OTHER POSSIBLE CAUSES:
- Lack of fixed background ventilation in the rooms where moisture is appearing - Relying on windows (purge ventilation) or window trickle vents can cause issues.
- Lack of adequate mechanical extract ventilation in 'wet rooms' kitchen, bathroom, WC, Utility room, etc. (Also note: sometimes a broken or poorly installed vent tube can be extracting moisture and pushing it back into the building).
- Gas fires in rooms - require hi & low background vent to expel moisture and gases.
- Building constructed & not meeting IS 440 technical guidance for timber frame systems for use in Ireland. ( Lack of fixed ventilated cavity ).
- Brakes in the VCL (Vapour control layer) behind the wall / plasterboard.
- interstitial condensation.
- Was a moisture risk analysis performed on the building / system ? - (WUFI).
- As the other poster mentioned - thermal bridging could also factor (if localized moisture spots?)
As you can see there are a myriad of factors to consider.
Rgds,
MIke F

statty

The outside of the wall is south facing.

I must look into the other factors - alot of info and things to consider!!

Thanks though

energyratinghom

Sorry to hear about your problem. Timber frame is so effective at eliminating these types of issues that were common place in old masonry built homes, but the frame is only as good as the engineer who signs off on the labour!

A few questions to establish what we are talking about here, and will be happy to help.

Firstly, What type of insulation was fitted originally?
And to be clear, is the insulation in between the studs in the wall, or are we talking external clad insulation on the outside of the frame?
(Fibreglass melting/falling due to poor installation is a common problem and easily remedied if identified as the problem, but need to ID the spec on the Vapour Barrier and Insulation first.

Have you taken Thermal Imaging pictures? Small cost, but valuable to your investigations before you go ripping!

Did you happen to take pictures of the build at stages ... particularly during the Insulating fitting?

Interstitial Condensation Risk Analysis can be undertaken, but at this
stage thats a little too late for preventive measures, but some thing to be noted for possible future corrective actions.

Is the damp patch near the ceiling and is is on Ground Floor or First Floor.

Is the house Dormer, Storey & half or two storey?

Thermal bridging is a common issue, but there are remedial details available, once you know the root cause for the issue.

ERH

statty

The insulation is in between the studs of the wall. The insulation is fiberglass - I will have to check on specifics.

I have not taken any thermal imaging photos or pictures during the building phase unfortunately.

The house is a story and a half and there is no dampness downstairs on the ground floor. It is only on the first floor. However, the sun room is attached to the ground floor wall (but not the first floor) so that is why it might not be affected.

Hope this helps!!And Thank you

archtech

statty wrote: »

The insulation is in between the studs of the wall. The insulation is fiberglass - I will have to check on specifics.

I have not taken any thermal imaging photos or pictures during the building phase unfortunately.

The house is a story and a half and there is no dampness downstairs on the ground floor. It is only on the first floor. However, the sun room is attached to the ground floor wall (but not the first floor) so that is why it might not be affected.

Hope this helps!!And Thank you

There's a strong possibility that the glass fibre insulation has fell/sagged to the bottom leaving no insulation behind the plasterboard in places. Thermal Imaging could identify this without having to go open up things . Without a site inspection we are very much second guessing . It would be best to engage an experienced professional

engineermike

Hi,
Thermal imaging would also be my first port of call. Some particulars of the type of timber frame might give an indication as to what the problem is ( i.e. if its with the system itself).
However thermal imaging will give good indications of insulant loss / sag. Thermal bridging, and or moisture spots.
Also leaks and broken pipes can be traced.
mike f

ann marie kelly

Hi statty. I am on another thread and Sas just told me about a heat recovery system. It might work in your case. Just Google HRV and you have all the info.

archtech

ann marie kelly wrote: »

Hi statty. I am on another thread and Sas just told me about a heat recovery system. It might work in your case. Just Google HRV and you have all the info.

Without finding out the source of the problem first, one won't fix it. Installing heat recovery could be an expensive way of solving the problem and will be expensive to install and run without a significant retrofit. A dwelling needs a good level of airtightness for heat recovery to work efficiently.

A demand control unit may help solve the problem, however you need to know the source of the problem first.

ann marie kelly

You are correct. I feel really sorry for this person. Problems in a new house must be heart breaking. Should her home not be still covered by insurance??/