Pumped cavity wall Insulation - merits

[Mattger1]

In 2006, my aunt developed a terraced building in Killarney. She knocked the existing house and rebuilt a shop/office on the street front (3 storey) with four appartments in the garden to the rear. The appartment construction consisted of two 4 inch block walls with a 4 inch cavity. Her builder decided to pump in the cavity insulation, following construction of the walls.
Today, all her tenants have condensation problems in the appartments, with mould forming on some of the walls. Even in bedrooms, there is condensation falling from window lintels, and tenants have to wipe down walls regularily.
In my opinion, we use cavity walls in this country to provide a vapour barrier, to prevent moisture which may penetrate the outer wall from reaching the inner leaf. Surely the cavity is compromised by filling the cavity with polystyrene balls as insulation, and this is part of the problem with dampness and condensation.
Please advise if my reasoning has value, and advise on how we might correct this problem.


Matt

[heinbloed]

You're right with the reason why cavity walls where developed in the first place.
To find a remedy to your existing problems one has to find the reason for the dampness. If this is because of faulty workmenship then the/your contract partner is responsible, sue him.
If you can't get him anymore then it would be the insurance company.

In principle the driving rain has to be kept away from the outer wall. The idea of having a cavity wall was nothing else: keep the dampness separate from the habitated area.
This means cladding, extension of the window cills and combining the reveals around doors and windows with the cladding. It is important to have the external cladding build in such a method that all moisture getting into the structure can 'breathe' away.The method is called a "ventilated cladding".

Before starting the job make sure there are no other ingresses into the wall, rising damp or pipe work going through, acting as a duct for all external moisture or being leaky themself.

If there is a chance increase the thermal insulation externally, at least at the known weak spots (you've mentioned the lintels being effected in particular).

But before starting with the job: make sure that the cause for the dampness is indeed the ingress of moisture from outside. Get a professional architect, structural/civil engineer in.They'll write you a report for the courts, for the insurance and to specify the repairs which needs to be done.
This time of the year is ideal suited to get a thermal image done with an infrared camera, it'll show the warm spots externally and the cold spots internally.
The professional might recommend a "dynamic dew point analysis" to be done. This is to make sure that the right remedial meassures are taken, for example the insulation might be to thin or in itself totally unsuitable from the beginning.

Once the wall is dry (cladded) the plaster at the internal walls should be removed to get rid of all prevailing mould spores. This will also be the right timing to take off a bit from the flooring/ceiling to check if hidden beams/timber work is already effected. Then re-plaster it.
Stay away from internal insulation.

The costs involved with the correct work can be high. Take the builder to the courts if necessary. You've mentioned that part of the building is used as a commercial property, your insurance for this part might cover the court costs (action against the builder) for this particular part. Check this with a lawyer, call your insurance as well to ask for advise.

And get more then one advise, better ask twice.

Good luck!

[dobelmpk]

Heinbloed, is of course correct.- and Killarney is a very humid place with driving rain .
However there are plently of houses which do have incavity insulation and do not suffer from the problems described.
There are other possibilities as well - What level of ventilation was included in the dwellings when they were renovated? Old properties would have had poorly fitting windows and these would have kept the house ventilated by default. If these are replaced with modern double glazed units without drafts, then and unless there are other forms of ventilation, the humid air created by living - breathing, boiling kettles etc has to go somewhere
Likewise some old houses might have been built without dampproof courses and again the ill fitting windows would have masked the problem.

You will need to get professional advice from an architect, or preferably a building surveyor.

Mould in buildings is a dangerous health hazard.

[sjones Aereco]

Please take this advise with advise, I work for a ventilation manufacture as the title suggests.
Ventilation is a huge problem in Ireland. Both under and over ventilataion.
We get calls on a daily basis just like this, buildings with ever increasing levels of air tightness and insulation with ventilation not keeping up with even the smallest progress in these standards.
In flats a common occurance is natural vents and intermtitent fans if at all. With no through put of air through vents unless pulled infrequently and badly by fans.
Check the relative humdity of the rooms, it will give you a good idea of the indoor air quality and effectivness of the ventilation.

Regards

Simon

[sjones Aereco]

Oh six week old baby in house hence post at midnight!

[profeskore]

The wall insulation should have a 25 yr guarantee by the installer,get him out to look at the job,possible problem is dirty wall ties and no weep holes in the bottom of cavity or too much glue used in places or areas of walls not filled by wrong drilling practice.It should be easily fixed.Thermal image is a good place to start.There are a number of good installers in Kerry,Sheehys seem to be one of the biggest.Also walls need to be plastered and not stone or brickwork.dRIVING RAIN WOULD ONLY EFFECT ONE OR TWO WALLS

[profeskore]

One simple thing is there may be no ventilation in your rooms,this would cause condensation,check vents are not blocked with insulation,if no vents are present put some in ,there might be vents on the windows,common problem also that builder didn't ventilate the building during construction may also be cause.

[jeremy.horwitz]

Cavity wall insulation is a proven and government recommended method of insulating homes in order to curb fuel poverty and toxic emission of carbon dioxide gases. Hence, every household must know about the basics and all the hows, whys, whats, when and wheres of this particular forms of insulating homes.
If you have a cavity wall, it is fast and easy to pump in insulation.
Also please don't confuse cavity blocks with a cavity wall. With a cavity block 80% of the heat loss pass through the block and only 20% crosses the air gap. So even if you could find and fill all cavities you would only fix 20% of the problem.

____________________
Greentech are specialists in a range of Cavity wall Insulations Services.

[Viking House]

Hi Jeremy

How do you fill in the gaps in the foam in the cavity that has shrunk?