West of Scotland, Motherwell
Wet rot, dry rot and woodworm in Motherwell
Motherwell, Wishaw and Bellshill have had more remedial damp work and more retrofit done to them than almost anywhere else we cover. A fair share of what we now find was caused by it.
- We look before we priceNo quote without a survey
- Written reportSomething a lender will accept
- West of Scotland onlyGlasgow to Ayr and Stirling
Motherwell and the towns around it were built for and by heavy industry, and the housing reflects it: a core of Victorian and Edwardian sandstone terraces near the centres, and around it a very large stock of interwar and post-war housing put up by the local authority, most of which has been in private hands since the nineteen eighties. The technical starting point is the one set out on theLanarkshire page: cavity walls, suspended timber ground floors and made-up ground that moves drains.
What Motherwell adds, and the reason it is worth its own page, is a long history of intervention. This stock has been damp-proofed, tanked, replastered, re-rendered, re-roofed, double glazed and, more recently, externally insulated, often more than once and often by different people working to different assumptions. A meaningful proportion of the timber decay we are called to here was set going by well-intentioned remedial work rather than by neglect.
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Three questions. You do not need to know which problem you have.
When the cure is the cause
This is uncomfortable to say about other people in the same trade, so it is worth being precise about the mechanism rather than vague about blame.
Damp at the bottom of a wall has several possible causes. Water arriving from outside at ground level is by far the commonest: a path or driveway laid above the level of the damp proof course, a gully that has settled, a downpipe discharging against the wall, a blocked airbrick stopping the floor void below from ventilating. Genuine rising damp, moisture drawn up through masonry by capillary action, is real but far rarer than the amount of injection work carried out would imply.
Where a chemical damp proof course is installed without those external causes being fixed, the water keeps arriving. And the treatment normally comes with a specification for dense waterproof replastering, which seals the inside face of the wall. The visible symptom disappears, which is why everyone believes it worked. The wall is still wet, it can now only dry outward, and any timber built into it or fixed against it is in a worse position than before. Joist ends, wall plates, sole plates and the battens behind a lined wall are all in exactly that position.
We see the result years later as wet rot in joist ends along one wall, or as dry rot where that wall meets an enclosed, unventilated floor or press. By then the plaster still looks immaculate.
Insulation retrofit, and the two details that matter
A great deal of the solid wall and non-traditional housing across Motherwell, Wishaw and Bellshill has had external wall insulation fitted under energy efficiency programmes. The insulation is not the problem and we are not arguing against it. Two details around it decide whether it causes trouble.
- Underfloor ventilation. A suspended timber ground floor needs air moving through the void beneath it, and that air comes in through airbricks at the base of the wall. When the wall gains a hundred millimetres or more of insulation, those vents have to be sleeved right through it to still work. Where that was not done, or was done and later blocked, the void stops ventilating and the floor timber begins to hold moisture.
- Rainwater goods. The outside face of the wall has moved outward. Gutters and downpipes have to move with it, and the downpipe still has to discharge somewhere that carries water away. Where brackets were reused or the shoe now sits over the wrong part of the ground, you get a concentrated stream of water hitting the base of a newly insulated wall every time it rains.
Both are easy to check from outside and both are worth checking yourself before you book anything.
Wet rot is much the commonest finding here, and that is the cheaper answer. Wet rot stays where the water is. Deal with the water and the affected timber can often be cut out and replaced locally without the extensive removal a dry rot outbreak demands. That is why the order of work on a Motherwell job is nearly always the same: find and stop the water first, replace the failed timber second. Anyone proposing the second without the first is selling you a repeat visit. Thewet rot page for the West covers what that work involves.
The older sandstone, and woodworm in the newer stock
The Victorian and Edwardian terraces near the town centres behave like older property everywhere: solid walls, joists into stone, and dry rot as the serious risk when rainwater goods fail. That is the minority of the housing here but it produces a disproportionate share of the expensive jobs.
In the post-war stock the recurring finding is woodworm rather than rot, for the same reason it turns up across Lanarkshire: roof and floor timber from the fifties, sixties and early seventies was frequently untreated softwood. Most of what we are shown is long dead, andworking out whether woodworm is still active is the first question rather than the last. If it is live, the woodworm pageexplains what treatment actually involves.
What to tell us when you enquire
Three things carry more weight here than anywhere else on our patch, because each one redirects the survey:
- Any previous damp work. An injected damp proof course, tanking, or replastering, with rough dates if you have them. If there is paperwork or a guarantee, that is genuinely useful.
- Any insulation retrofit. External or internal, and roughly when.
- What is outside the affected wall. A driveway, a path, a raised bed, a downpipe, an extension. In this town that is frequently where the answer is.
If you are not sure which of the three problems you are looking at, that is the usual position and nothing to apologise for. Atimber survey covers all three in one visit, and the report will say plainly if the honest answer is that the timber is sound.
Questions we get from Motherwell and Wishaw
We had a damp proof course injected a few years ago and it is still damp. What went wrong?
Possibly nothing was ever wrong with the wall. Genuine rising damp is far less common than the volume of injection work carried out would suggest, and the symptoms it is blamed for, damp at the base of a wall and rotting skirtings, are produced far more often by something outside: a raised ground level, a leaking gully, a blocked airbrick or a defective downpipe. If those were not dealt with, injecting the wall changed nothing about the water reaching it. The other possibility is that the injection was fine and the replastering specified with it is now the problem, which is the next question below.
Why would replastering make anything worse?
Because of what gets specified with it. A dense, cement-rich, waterproof render is commonly applied up the wall after a chemical damp proof course, and it does stop moisture appearing on the plaster face. It does not stop moisture being in the wall. What it does is push it elsewhere, usually higher up or deeper in, and it takes away the wall’s ability to dry inward. Where timber is fixed to or built into that wall, joist ends, sole plates, battens behind a lining, it is now sitting in masonry that cannot dry, which is exactly the condition rot needs. The plaster looks perfect while the timber behind it goes.
Our house had external wall insulation fitted. Should we be worried?
Not on principle, and it is worth saying that the insulation itself is usually fine. What we look at is the detailing around it, because that is where problems come from. Two things in particular: whether the underfloor airbricks were properly sleeved through the insulation so the void below the floor still ventilates, and whether the rainwater goods were reset far enough off the new, thicker wall face to still discharge clear of it. Get either wrong and you have a suspended timber floor with no ventilation, or a downpipe emptying against the wall. Both produce rot, and neither shows on the outside.
Is it worth surveying if the damage looks small?
Usually yes, because the visible damage is rarely the extent of it. Soft timber at the front edge of a floorboard by a bay window generally means the joist end behind it has been wet for longer than the board has. The point of the survey is not to confirm the bit you can already see, it is to find where the water is coming from and how far the decay has travelled from it. Sometimes the answer is genuinely reassuring and the report says the timber is sound and nothing needs doing, which is a result worth having in writing.
Do you cover Wishaw and Bellshill as well?
Yes, and Newarthill, Carfin, Holytown, Cleland, Overtown and Craigneuk on the same terms. The building stock across all of them is close enough that most of this page applies unchanged. Hamilton, Blantyre, Larkhall and Uddingston are also inside the patch and are covered from the same base, so none of it is a special trip.
Book a survey
Three questions. You do not need to know which problem you have.