In a conservation area, repairing your sash windows like for like rarely needs permission. However, replacing them with a different style often does, and an Article 4 direction can make permission compulsory. Rules differ by council and by street, so ask your local council before you order any new windows.
What a conservation area is
First, what is one? It is an area of special interest because of its buildings or history. Government planning guidance says its character is worth keeping.
Also, councils pick these areas, not homeowners. They must also check each area from time to time.
So the boundary is on public record. Your council can tell you if your street is inside one. Check its website for a map.
Why windows matter so much
Windows shape how a street looks. For example, a row of old terraces with matching timber sashes reads as one design. One plastic window in the middle breaks the pattern.
That is why councils watch windows closely. Wandsworth Council, for example, says that plastic-looking windows are not likely to be acceptable in place of timber. It also asks residents to keep and repair original windows where they can.
Repair is therefore the easy route. It keeps the original look, so there is little for the council to object to. Our guide on whether to repair or replace sash windows looks at the other side of that choice.
What an Article 4 direction does
Most houses have permitted development rights, because the law lets owners make some changes with no planning application. Replacing windows is one example.
However, an Article 4 direction takes some of those rights away. Haringey Council says it lets a council limit those rights in an area.
It can cover small changes to windows and doors. Such changes can slowly wear down an area’s look.
As a result, the same job can need an application on one street and none on the next. Haringey, for instance, applies Article 4 directions to four of its conservation areas. Wandsworth lists eight conservation areas with directions in place.
So never assume, because a neighbour’s recent window change tells you little. They may have had consent, or the work may be older than the direction.
When you do and do not need permission
Four cases come up again and again. Here is a plain guide, though the rules stay with your council.
First, repair. Mending a sash, fitting a new cord, splicing in new sill timber or adding draught seals does not change how the window looks. The council guidance above turns on a change of look, so like-for-like work is the low-risk route. Even so, ask your council first, and always do so if the home is listed.
Second, a change of look. Wandsworth’s guidance says that in conservation areas, changing windows to a different appearance needs planning permission for a single home. Painting existing windows is excluded. Where an Article 4 direction applies, residents must always ask the council.
Third, flats. The same council notes that flats, and houses split into flats, have no permitted development rights. Permission is always needed. That can catch owners out, because many period houses are now flats.
Finally, listed homes. The 1990 Act bars works that affect a listed building’s character unless the council agrees. That means you need consent first. Our listed building and conservation sash windows page covers how we approach those homes.
How it can go wrong
Picture a buyer who moves into an old flat with a draughty window. Then they order a new plastic one. If the street is a conservation area, the council may later say the work needed consent.
That is a costly mistake, so a quick check first makes sense. A call to the council is short. Taking out a window that has gone in is not.
Also, do not rely on a fitter who says it is fine. Ask for that in writing. If the answer is vague, ask the council yourself. Keep every reply, because a buyer’s solicitor may ask for proof when you sell.
Like-for-like repair
Councils often say like for like, since that is what keeps a street looking right. In short, it means a repair that matches the original in material, shape and finish.
For example, for a sash, that covers the glazing bars, the horns, the timber thickness and the paint. A new bit of sill should match the old one. A new sash should have the same proportions as the old.
That is what we do when a sash is beyond repair. Our replacement sashes service makes new sashes to match the old ones, so the window looks the same from the street. We handle listed and conservation work case by case.
Wandsworth’s guidance backs this up, and it is still a useful test. It says replacements must look like the original materials. The design should also match the glazing pattern and style.
What about draught proofing and double glazing?
Many owners want warmth as well as heritage. Fortunately, you can have both, while keeping the old timber.
First, draught proofing sits inside the window and does not change its look. Secondary glazing sits behind the original window. Slim double glazing changes the glass itself, so it needs more care. Our comparison of draught proofing and secondary glazing sets out the differences.
If you want double glazing in a listed home, read our guide to double glazing listed sash windows. Above all, ask before you buy. Councils can say yes to one product and no to another. Style matters too, so see our upcoming guide to Georgian and Victorian sash windows to identify yours.
Repairs that avoid replacement
Most sash faults can be fixed without a new window. A snapped cord, for example, is a small job. Our guide to broken sash cord replacement shows how little the fix changes.
Because repair keeps the original, it also keeps your options open. If you ever want to ask for something bigger, you start with a sound window.
Costs
However, repair costs less than most people expect. Our price list gives an overhaul with draught proofing as £188 per window, and a new sash as £190. Ornate or multi-bar sashes cost more.
Then, for more detail, read our guide to sash window repair costs in London. The costs page lists every figure.
Conservation areas across London
Conservation areas sit across many London boroughs. Their character varies, yet sash windows turn up in plenty of them.
In the East End, for example, you will find older terraces among sash window repairs in Tower Hamlets. South of the river, period streets in sash windows across Southwark include both Georgian and Victorian houses. Further out, you will still find timber sashes in homes across Brent.
Because rules differ, always check your own borough. Many councils publish guidance for each area, and it may say which window styles they expect.
How to check your own property
First, visit your council’s website, because that is where most keep their maps. Find your street. Then look for any Article 4 direction that covers it. Finally, read any window guide the council has put out.
If you are still unsure, call the planning team. Ask if your work needs permission. Keep the reply in writing, because it protects you if questions come up later.
Questions to ask the council
Keep your questions short and clear. Ask if your street is in a conservation area. Then ask if a direction cuts your rights, since that decides what you can do.
Next, ask if your job needs consent, and what the new window must look like. Send the council a photo and say what you plan to do. That way, you get a clear answer and no nasty surprise.
Next steps
Please tell us if your home is in a conservation area when you get in touch. Since the rules shape the job, we can then plan around them. Request a free site visit and written quote through our contact page. We cover all Greater London postcodes, and our work carries a five-year guarantee on labour.