Buying a house with dry rot

Of everything a Scottish home report can name, dry rot is the one that deserves the reaction you are currently having. Not panic, but genuine care. It is the only timber decay problem that will not stay where you found it.

The short answer to whether you should proceed: you can buy a house with dry rot, and people do it every week, but only once somebody has established how far it has travelled. Every other question, including the price, depends on that one, and it cannot be answered from a doorway.

Why dry rot is different from everything else in the report

Wet rot, which is far more common, stays local to the water that caused it and dies when the timber dries out. Fix the leak, replace the soft wood, and it is over. Woodworm is an insect in damp timber and is usually historic anyway.

Dry rot, Serpula lacrymans, does something neither of those does. Once established, it conducts water along its own strands, which means it can grow away from the moisture that started it, through and behind solid masonry, under floors, up through a wall and into a flat above. That is the entire difference, and it is why the same fungus in two different buildings can be a two thousand pound job or a thirty thousand pound one.

The practical consequence for a buyer is that the visible patch is not the problem. The problem is the part behind the plaster, and nobody standing in a hallway can tell you how big that is.

What the home report is really saying

A single survey is a visual inspection, done in under an hour, without lifting floors or opening up walls. When a surveyor writes dry rot and applies a category 3, they are not telling you the extent. They are telling you they saw something they were not prepared to sign off, and that a specialist needs to open it up.

Look for four things in the wording, because they change the reading:

• Where it is. Ground floor, bay window, under a bathroom, against a gable, at the foot of a stair. All of these tell you something about the water source.
• Whether they saw a fruiting body. The red-brown pancake with white edges is the reproductive stage, and it usually means the outbreak has been running a while.
• Whether moisture is mentioned in the same paragraph. Dry rot needs around twenty per cent timber moisture to get going. Something wet it.
• Whether access was restricted. A surveyor who could not get into the void or the cellar has told you the least useful thing possible, which is that they do not know either.

The property questionnaire is worth reading closely too. Previous treatment, a historic leak, work done to the roof or the gutters: the seller has to answer, and the answers often explain what the surveyor could only describe.

The one thing that decides the price

Everything hangs on how far it has spread, and finding that out means opening up. Lifting floorboards, taking off skirtings, removing plaster back to sound masonry, getting into the void beneath.

That is intrusive, it is the seller’s house, and it is the single biggest practical obstacle in a Scottish purchase, because your timescale is short and the property is not yours. Ask anyway. A seller who wants the sale will usually allow a specialist in, and a seller who refuses has made a decision you should factor into your offer.

What it costs

There is no single figure, and anybody who gives you one over the phone is guessing. The realistic range runs from a localised repair in one room to a job involving several rooms, a neighbouring flat and structural timbers. What drives it is access, how much masonry has to be exposed, and whether anything holding the building up has lost section.

The ranges we work to are on dry rot treatment cost, and the reason every figure there is a range rather than a price is that the extent is genuinely unknown until somebody opens up.

Three costs buyers routinely forget to add:

1. Making good. Plastering, joinery, decoration and flooring after the treatment team leaves. This is frequently as much again as the treatment.
2. The water. The leaking gutter, the failed downpipe, the cracked hopper, the blocked airbrick. Not fixing it means paying for the treatment twice.
3. Somewhere to live. Significant work to a floor in a one-bedroom flat may not be compatible with living in it.

Lenders, retentions and the timetable

A named dry rot outbreak will usually produce one of three outcomes from a lender: a request for a specialist report before they will proceed, a retention held back until the work is signed off, or in the more serious cases a valuation that reflects the property as it stands.

None of these is the lender refusing. All of them need paper, and the paper they want is a report from a firm that carries out this work, setting out what was found, what is proposed and what it costs. That is what a dry rot survey is for, and it is the document your solicitor will use to negotiate.

The timing is the hard part in Scotland. Once missives conclude you are committed, and everything you wanted to negotiate had to happen before that point. So the order is: get the specialist in, get the report, then let your solicitor work with it. Not the other way round.

Flats, closes and the neighbour problem

This is where a Scottish purchase gets its own set of complications, and where buyers get caught.

Dry rot in a tenement does not respect the boundaries of your title. An outbreak that starts in a common close, or in the flat below, or behind a shared gable, is a building problem rather than a flat problem. Under Scottish tenement law the roof, the gutters, the downpipes and the structural walls are usually common, which means repairs are shared, which in practice means agreeing them with every other owner in the stair.

That has two consequences worth understanding before you offer:

• The cause may not be yours to fix. A failed shared downpipe soaking a gable is a common repair. Your treatment is wasted until it is dealt with, and getting a close to agree on anything takes time.
• Your share of a common repair can arrive later. Ask the seller, through your solicitor, whether any common repairs have been discussed, proposed or voted on. The property questionnaire covers some of this, but a direct question is better.

If the outbreak sits inside your own flat, with a cause inside your own flat, the job is far more contained. Establishing which of those you are buying is worth more than any negotiation tactic.

The five questions to get answered before missives

1. Is it actually dry rot? Not wet rot, not mould, not an old outbreak. The difference is set out in wet rot or dry rot, and it changes the cost by an order of magnitude.
2. Is it live? Dried out and cut off from its water source, it is finished. That finding saves the most money of any in this trade.
3. Where is the water coming from? If nobody can answer this, nobody can price the job, because the treatment is only half of it.
4. How far has it gone? Which rooms, which walls, whose flat. This is what somebody has to open up to find out.
5. Has anything structural lost strength? Joist ends, lintels, stair strings, bearings. This is the question that turns a repair into a building job.

So should you buy it?

Buy it if the extent is known, the water source is identified and fixable, the figure is written down, and the price reflects it. Thousands of perfectly good Scottish flats have had dry rot dealt with properly and are worth no less for it afterwards.

Walk away if nobody will let a specialist open anything up, if the cause sits in common property and the other owners are not engaged, if structural timbers are involved and the seller will not move on price, or if the honest answer to “how far does this go” is still “we do not know” on the day your solicitor needs to conclude.

A dry rot survey is the thing that turns all of that from anxiety into a number. If you are working to a date of entry, say so when you book, because it changes how the job is scheduled.