Wall properties for 20 year old house

Claire · Post by **Claire** » Sat Feb 04, 2012 5:04 am -1100

Could someone please tell me what the necessary changes are to the properties of a cavity wall which would have been exposed to weathering for say 20 years? I know the moisture content for example would increase but to what degree?
This is for my dissertation so any help would be great

Daniel · Post by **Daniel** » Thu Feb 09, 2012 12:57 am -1100

Dear Claire,

can you please specify your question a little bit more...? I don't really understand what information you need.

And of course there are many different types of walls - also in different countries...

Daniel

Claire · Post by **Claire** » Thu Feb 09, 2012 4:44 am -1100

Daniel wrote:Dear Claire,

can you please specify your question a little bit more...? I don't really understand what information you need.

And of course there are many different types of walls - also in different countries...

Daniel

Well im researching into how effective insulation is when injecting the cavity of an existing building and comparing it with insulation fitted during construction.

My location of my simulations is in the lake district, England, an area which receives the most rainfall in the uk per year.

My wall consists of:
Interior:acrylic stucco-solid brick masonry-insulation-concrete block-lime plaster-gypsum plaster:Exterior

So for a 20 year old house i know there will be deterioration to the structure and difference in moisture content for the materials compared to when it was originally built but im not sure to what extent.

Thanks

Daniel · Post by **Daniel** » Thu Feb 09, 2012 8:55 pm -1100

So this is really difficult to answer. As far as i know no reliable models for ageing of materials depending on hygrothermal conditions are available.

Of course the hygrothermal conditions can be simulated - but you need to know ore estimate the material properties. For me it's surprising to use an exterior rende containign gypsum - this is very unusual in Germany.

The water content in the whole wall depends mainly on the water absorption coefficient and diffusion permeability of the exterior render - so these are the most important information you need.

If the insuluation is in the concrete block cavities it will increase the moisture on the exterior part and decrease the moisture in the interior part of the wall (the first part becomes colder - worse drying - the second one warmer - better drying).

I hope this helps a little bit...

best regards
Daniel