Roof, boiler, damp, rewiring: what to do first when you cannot do it all

Over the past three years I have paid for a new combi boiler at £2,500, a partial rewire at £2,500, a roof repair at £800, a full roof replacement at £6,000, damp treatment at £4,000, and internal wall insulation for one room at £1,500.

None of that added a penny to any of those houses in the way a kitchen does. That is not a complaint. It is the whole point of this kind of work, and understanding it will save you more money than any of the individual jobs.

What this work is really buying you

Here are three real numbers from my own transactions.

Buying a house, damp in the conservatory and a cut-off front porch got me around £8,000 off the price. A boiler that needed replacing got me £2,000. Selling a bungalow, black damp appeared on the main bedroom wall, and £10,000 came off what I got.

That is what essential work is for. You are not adding to the price. You are removing a deduction that a buyer, a surveyor or a solicitor will otherwise find and take. The money is exactly as real either way. It just arrives as a subtraction that never happens.

The boiler is the one exception. In my experience a new boiler does add value. Every house in this country depends on one, the weather sees to that, and a buyer knows it before they have taken their coat off.

The order, when you cannot do everything

Given £10,000 and all of these problems at once, here is the order to work in.

Roof. Boiler. Damp. Rewiring. Insulation.

How bad each one is can move things around, and it is an order, not a rule. An active leak beats everything. A boiler that has stopped in January beats everything. But as a default, with nothing screaming at you, that is the sequence.

The two people most often get wrong sit at opposite ends of it. Roof and damp are the ones that get ignored. Insulation is the one that gets treated as urgent when it is not.

The roof, which nobody looks at

Most people never go near their roof until water comes through it.

Mine started as a leak with old beams and broken tiles. I had it repaired for £800. Then another section went after heavy rain and I replaced the whole thing for £6,000. On that second decision: the full replacement probably was not necessary. I did it for peace of mind rather than because it was forced.

You cannot tell the state of a roof from the ground. Somebody has to go up, lift tiles and look underneath. That is a dangerous job on a two-storey house, so pay a professional to do it and take the report.

The boiler

I do not use a cost rule or a hard age limit. A boiler is like a car. If you service it every year it will keep going for a long time, and how it has been looked after tells you more than the date on it.

Mine went because it kept breaking and throwing errors, and I put off replacing it. Winter arrived, the pipes froze as well because the old installation had never been done properly, and we had a lot of cold days. That delay did not cost me more money. It cost a season of being cold in my own house, which I would now weigh more heavily than I did.

My replacement was a fixed quote through my energy company and nothing appeared afterwards. The one thing that does change the number significantly is moving the boiler to a different position, which added about £2,000 or more in my experience once you count the pipework, the route, the drilling and making everything good again.

Second-hand boilers come up. They are cheap, and the saving disappears the moment you factor in a certified installer, which you need anyway. New comes with a warranty and a guarantee, and for most people that is the end of the argument.

Damp, which is the one that loses you the sale

Damp cost me £10,000 on one sale and got me £8,000 off one purchase. It is the most expensive item in this article by a distance, and the reason is not the repair bill.

It is the smell. A buyer walks in and smells it. They might love everything else about the house, and they leave anyway. You cannot stage around it, you cannot paint over it, and fixing it properly is not cheap. There have also been several years of news in this country about damp in homes and the health problems that go with it, and buyers have absorbed that.

Doing it properly starts before anybody quotes you for a treatment. Find the cause. Is it a leak, a defective roof, cracked render, condensation? Fix that first, because everything after it is wasted if the water is still arriving.

Then the treatment depends on what you actually have. Rising damp is usually a damp-proof course injection with the walls replastered. Penetrating damp means water getting in from outside through a defect in the roof, a wall, a window or a floor, so the work belongs on the outside. Redecorating the inside without fixing the way in is treating the symptom and leaving the cause. Garages and conservatories are their own case, because their floors were never built up in the same layers as the rest of the house. In a garage the moisture can come straight up through the concrete slab, so a floor membrane matters, especially if you are turning it into a room. And ventilation matters everywhere, most of all in a converted garage.

Rewiring, and why it goes first if you are renovating

My partial rewire took seven days and cost £2,500. Living there through it was genuinely unpleasant: noise, dust through the whole house, walls chased open, and the power going on and off. Our fridge freezer developed problems during it and had to be emptied.

That is why damp comes first. If electrical work is on your list, do it first. It is the most disruptive job in the house and everything else has to be redecorated around it anyway.

Whether you need a full rewire is not a judgement to make from the internet.

If the wiring itself is sound and you only want a new consumer unit, that is a perfectly reasonable job on its own. Same if one or two circuits are causing all the trouble.

Insulation, the one that can wait

Insulation is the item on this list to leave until last, and people do wait, usually without noticing they have made a decision. They put the heating on more, they add a plug-in heater in the cold room, and they get on with it.

That is fine, up to a point. Mine was one room, an old added-on bathroom that was freezing, and £1,500 of internal wall insulation dealt with it.

If your reason for doing it is how the house feels, and not a line on a certificate, the order that has worked for me is loft and roof first, which makes upstairs much warmer in winter and noticeably less baking in summer. External wall insulation second, which takes the cold edge off the ground floor. Those two have made more difference to how my houses felt than anything else I have done in this category.

Fix it, or price it in and let them deal with it

Not all of this has to be done before you sell.

Rewiring and insulation can reasonably be left to the next owner. They are not emergencies, they do not smell, and a buyer can plan them.

Roof, boiler and damp are different, and how different depends on the season and on how bad it is. An active leak has to be fixed, full stop. Damp should be fixed, for the reasons above, and it belongs top of the pre-sale list every time.

The boiler is mostly about convenience. It is £1,000 to £2,000 and an easy job, and doing it means a buyer does not arrive at a cold house with cold water and a contractor to book in their first week. There is one case for leaving it: an old house, empty, chain-free. Then the new owner is expecting to do work, and the boiler is one line on a list they have already accepted.

Paperwork has never cost me much on any of this. Where something is missing, indemnity insurance usually covers it and the seller pays. The exception is where the work genuinely has to be redone, and then you are giving a discount whatever the paperwork says.

Knowing whether you need the work at all

There is no trick. Unless you are a specialist in that trade yourself, you are not going to out-argue somebody who does it every day.

What works is duller and it works reliably. Get several quotes and several opinions on the same problem, and see how many of them say the same thing. Compare them against what other people actually paid. The Velux window and the full re-roof is exactly that story: one quote said replace everything, another said fix the window, and the second one was right. I would not have known which without asking twice.