Damp in Old Cornish Properties
- Published: 24 July 2016 24 July 2016
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Do you remember this time last year putting those expensive leather shoes in the wardrobe ready to get out again for the winter? And as the colder weather started to draw in again do you remember reaching into that same wardrobe and pulling out those valuable shoes to wear once again? Then you must remember the horror and that awful sinking feeling as you saw that those once beautiful shoes were now covered in a horrid green/grey dusty smelly mould.
When cob buildings were first occupied by dwellers there was a constant heat source from one or more open fire. Boiling water, cooking, baking etc. took place all day, every day. This relatively high internal ambient temperature and the thickness of the walls, as well as thatch, made for an almost damp-free existence. Adopting these ways today is impractical, and time consuming. Modern living allows little time and lots of restriction on such practices. However, the installation of under floor heating, preferably with a sustainable power source, has proven to be beneficial in the reduction of damp. Correctly installed and carefully regulated, this is an efficient and cost effective addition to most old buildings.
There can be all sorts of reasons why we have damp in our old properties in Cornwall, some could have been caused by age or bad building practices many years after the property was built – we have all witnessed the disasters of the 70’s and 80’s on our precious old buildings!
Some of the more common causes are:
Failed or leaking rainwater disposal systems
If your drainpipes are cracked or broken and the water is running down the side of the building it will inevitable cause water penetration and damp in that specific area. Having these replaced or repaired can make a huge difference to the presence of damp.
Guttering and facia boards must be in good condition with no leaks and have a suitable fall toward the running outlets. Downpipes should be leak-free and secure. All downpipes should fit directly into the gulley’s and flow into the land drain.
Deteriorating roofing elements
Much like having poor drainpipes, if your roof is poor you will suffer with damp problems. Broken, slipped or missing roof slate/tiles must be replaced, especially over the wall head. Hip and half-hip ridge tiles (tiles that fit over where roof sides meet), where applicable, must be secure and watertight. If hip tiles are not used, then the appropriate fish-tail flashings (the slight opening and splitting of a metal cramp to afford a better grip) must be in good weather proof condition.
If your cladding, the outside material used to face your walls, has cracks, bubbles, bare patches or it is crumbling, flaking or showing other signs of disrepair it could be causing your damp problems. Water could have penetrated to the substrate, the underlying wall, and could cause damp issues. Remove all existing impermeable applications, for example, current renders, cement based plasters and cement pointing. It is recommended that this should be done using hand tools, not machinery, only so as to not damage and/or disturb the substrate.
External ground level in immediate contact with the walls
As with most old properties the landscape around them had probably changed dramatically since it was first constructed and that could include the level of the ground around the building. If the level is too high and is coming into contact with the outside walls of the building this will inevitable cause damp.
The earth needs to be excavated and a channel introduced to allow air to circulate and for the property to breathe.
Again, as with most old buildings the landscape around them has changed and this can include the growth of trees and other vegetation around the property. If this is overhanging and preventing light and air circulating the property this could also cause a problem with damp. Old properties a like living things, they need to breathe and to have access to air and light.
Climbing plants i.e. Ivy
Cut-back or remove all vegetation in close proximity to the wall. Climbing ivy should be severed at the root base and left to die-off naturally. Removal of living ivy from the wall, especially if water penetration to the substrate has occurred, can result in unnecessary damage to the cob and/or stonework.
Poor or absent land drainage.
The installation of land drains at the base of all external walls has three main functions. Firstly, rainwater run-off from the wall itself will naturally find its way down to the drainage trench. Secondly, all rainwater from the roof, via gutters and gulleys, will go into the drainage pipe. And finally, any water at ground level will find its way into the trench before reaching the base of the wall. Capillary movement of water to the wall base would be negligible. All land drain pipes should run to a suitably distanced soak away area.
Unfortunately the total eradication of damp in old buildings in Cornwall is virtually impossible to achieve.
However, significantly reducing the levels of damp can be achieved by adopting some or preferably all of the procedures described.
All buildings and walls are different and the extent and presence of damp varies, however in our experience, here in Cornwall, these methods have proven successful in damp limitation.
We fully understand that undertaking all of these procedures is not always possible. Practicably, property boundaries, the lay of surrounding land and cost may prevent some or all of these procedures being executed in full, however with a full understanding, care and the use of appropriate materials damp limitation on Old Properties in Cornwall can still be achieved.
If you have an old property and suffer damp problems in Cornwall and would like advice to limit and prevent damp ingression in Cornwall, please Contact Us.
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