cavity filled damp in wall ?

when i bought my house the external wall was completly sodden. It had previously been cavity filled a few years before. i have heard from neighbours that since this was done there had been problems with damp. However due to the extent of the damp the whole outside wall was hacked off allowed to dry out and completly re rending, also the inside of the wall was hacked off and re plastered. now 1 year on i have patches of damp showing on the upsatirs wall. Cant afford to do anything else, what should i do. Sinlge women on her own with no one to ask and more ideas. please help

Hi

One question - does the wall face prevailing winds - that is a South Westerly or North Easterly direction?

The reason for asking is that this would in part account for the problems that you are faced with.

Regretfully, you have been given some poor advice as it would have been far better to have spent the money on removing the insulation material.
This may sound drastic, but the problem you have is related to the insulation material becoming damp (even saturated from what you have originally described) which is possibly more to do with condensation than penetrating rainwater.
The problem is the remedial work carried out to date would never have fully resolved the problem in the first place - but in fairness to the builders they would not have been in a position to known this unless they had a high degree of technical knowledge or perhaps they were reliant upon others who should have known better!

It is highly likely that the insulation material was still sodden when the rendering and re-plastering works were carried out as it would have taken months of dry weather for the cavity insulation to dry out!
Too add to your woes the condensation zone with your type of building construction is likely to occur around the point where the insulation material meets the external wall - the problem being worse in winter. Hence the reason why the external wall was so damp.

Trying not to get too technical - but in plain english (hopefully) warm air holds more moisture than cold air and when the warm air cools down through temperature differences i.e. when meeting colder air or a colder surface the air becomes saturated and moisture is deposited either on the surface or interstially (check out a dictionary if you are unsure of the meaning or even better do a web search on google!). Regretfully the work done on your house to date would not have resolved the condensation problem, and as the insulation is damp/wet it is basically making matters a lot worse for you as the insulation properties of the cavity wall are now far worse than had no cavity insulation been put in in the first place.

I would personally consider that the only solution to your problem would be to add some internal insulation to the external facing walls. British Gypsum do a thermaline 'super' insulated plasterboard (there are other manufacturer's but I tend to use BG as a point of reference) which can be stuck to the existing wall surface - this product has a high vapour resistivity and the material would assist in keeping the warm moisture laden air in the room. You could tackle one room or even one wall at a time as finances become available.

You may have to live with the cavity insulation as it may be horrendously expensive to remove, over time it should dry out - given that we have an extremely good summer, but how badly affected the insulation material will be is a mute point.

One question does come to mind - was any guarantee for the cavity insulation passed on to you when you purchased the house as you may have some recourse to the installer/manufacturer?

Apologies for having gone on so long, but I would hope that you are now aware of the nature of the problem that you are faced with and I sincerely hope that this discussion is of assistance to you.

Regards

thank you so much, it is what i expected then, but its nice to hear from someone else who knows what they are talking about. not sure about the plasterboard thing it was lined with that in the kitchen when i bought the house and that was sodden through as well.
I think the only answer is as you said and remove it. I have a guarentee from the people who put it in, so i will get in touch with them and try and fight it out to get it removed. Any advise you can offer on that would be grateful.
kindest regards desi x

Hi

Your first point of contact should be your buildings insurance company.

Also forget about the comments on condensation as this alone would not be causing the extent of the problems that you are faced with.

The simple fact of the matter is that the cavity insulation is breaching the cavity by two paths - 1. penetrating rainwater travelling across the cavity wall ties (cavity wall ties are designed so that any penetrating rainwater falls of the ties at about midpoint of the cavity) - this is no longer occurring and the rainwater is able to cross over this point creating localised areas of dampness inside the building;
2. The insulation material in contact with the wall ties is becoming saturated by the penetrating rainwater and also the rainwater that should be falling off the ties and down to below dpc level is instead saturating the insulation material. Hence the severity of your problem.

Your insurance company should be in a position to instruct further investigatory works to take place, samples of the insulation material should be taken to ensure it is suitable as a cavity wall insulation material, and also to confirm whether or not the insulation material is still damp/saturated (which will determine how successful the initial remedial repairs have been!) Also, a non intrusive damp survey should be carried out to determine the extent of any residual dampness both to the internal and external walls.

From this information it should be possible to determine the course of action that will need to take place to remedy the situation.


Regards

Can i ask here, is all cavity wall insulation likley to give problems or is it only the older stuff that was put in there in the past.

All cavity wall insulation is capable of causing internal damp problems, depends on the condition/state of the cavity, for example builders were notorious for not keeping the wall ties clean during the building of the walls and mortar snots could regularly be found on the ties which did cause some problems in some houses and that was without any insulation. Once you add the insulation you increase rather than reduce the problem, some people may have a misconception that it may have improved the situation. The problem is the penetrating rainwater breaches the ties with greater ease.

In a small number of cases even PIR foam cavity insulation can agravate the situation, although I would mention that the main problem with injected PIR insulation is the 'off-gassing' of the foam, which can create obnoxious smells and in some cases people have become sensitised to the smell and it has ruined the quality of their lives.

Regards