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Do I need a building permit to remove a wall?

As a rule, yes, if the wall is load-bearing — because then you're changing the house's structure. A plain partition wall usually doesn't need one. The building authority makes the call.

The principle: it's the structure, not the demolition, that triggers the requirement

Building control is fundamentally about making sure buildings are safe. So the dividing line isn't whether you tear something down, but whether you change something that affects the house's load-bearing capacity, fire safety, escape routes, or how the home is used.

Taking down a lightweight plasterboard wall between two rooms changes none of that — the house stands exactly as solidly afterwards. Taking down a load-bearing wall changes how the load from the floor above and the roof travels down to the foundation, and that's precisely what building control exists for.

So the whole question of whether you need a permit hangs on another question you can't answer yourself: does the wall carry anything?

Is the wall load-bearing? Neither you nor an app can decide that

Whether a wall is load-bearing depends on what sits above it and how the load travels down through the house. That's hidden behind plaster and drywall. You can gather clues — wall thickness, whether the wall continues through the storeys, which way the floor above spans, whether there's a beam above it — but clues aren't an answer.

A LiDAR scan only sees surfaces. HouseSense can measure the wall's length, thickness and height and draw it to scale; the app never decides whether the wall is load-bearing, and it shouldn't. An app can measure the wall. It can't decide what the wall is carrying.

That judgement has to come from a building surveyor or a structural engineer who has been to the site. If the wall turns out to be load-bearing, it's also the engineer who does the calculations and designs the replacement support — typically a steel or glulam beam — that the authority and the contractor will work to.

How to approach the building authority

Contact the building authority for the address before you book any contractors. In most places they're happy to answer a specific question about a specific address, and asking costs nothing.

What makes the enquiry quick and useful is being able to describe the project precisely. Have these five things ready:

1. The address and what type of home it is (detached house, terraced house, apartment, co-op).
2. Which wall it is, marked on a floor plan — not described in words like "the wall between the kitchen and the big room".
3. The wall's dimensions: length, thickness and room height, and how wide the opening needs to be.
4. Whether the wall is thought to be load-bearing, and whether an engineer's assessment already exists.
5. Whether the number of rooms or their use changes — for instance, whether two rooms become one, or a room's status changes.

This is where a measured floor plan helps concretely. HouseSense produces the floor plan as a PDF with measurements and areas from a scan or a drawing, and you can send it as an attachment instead of explaining it in prose. Processing doesn't speed up because you're polite — it speeds up because there's nothing left to ask about.

Living in an apartment, co-op or terraced house? Then there are two layers

In an apartment or co-op, the authority isn't the only one you need to ask. The owners' association or co-op board usually has a say too, because load-bearing walls, party walls and shared installations typically belong to the common property — not to the individual home.

Read the bylaws, and ask the board in writing before you go any further. This is one of those situations where asking first is markedly cheaper than asking forgiveness afterwards: an unauthorised opening in a party wall can be ordered restored at your own expense.

The same applies in terraced houses: the party wall against the neighbour is a fire and sound barrier, and it's never touched without a professional and the necessary permits.

Remember to get the change registered

If the renovation changes the home's area, the number of rooms, or a room's use, the public building register usually needs updating. Registers differ by country in name and in exactly what they require, but it's always the homeowner's own responsibility to make sure the information on file is correct.

Removing a wall between kitchen and living room rarely changes the registered floor area — the principle is that the register states the area measured to the outer face of the exterior walls, and internal walls count in that figure whether they're standing or not. But the number of rooms often does change, and that's information read by buyers, insurers and authorities alike.

A practical tip: keep both the "before" floor plan and the "after" floor plan, along with the engineer's paperwork, the permit, and the contractor invoices. That folder is worth its weight in gold the day the home is sold — and it's hard to reconstruct five years later.

The paperwork is a line item in the budget — and it comes first

The advice and the permit aren't free, and both costs fall before the contractor quotes in the timeline, not after. You can't get a real quote for a replacement beam until someone has calculated how big it needs to be.

Budget for an engineer's assessment and calculations for an ordinary beam replacement in a detached house as a real cost in its own right — where you land depends mostly on how big an opening is being calculated and how much sits above the wall. On top of that there can be a fee for the building case itself; that's set locally, in some places by hours spent, and it varies a great deal from place to place, so get that figure from your own authority rather than guessing it.

Processing time varies just as much. Build time into the plan, and don't book the contractor to a fixed start date until the permit is actually in hand.

What to avoid

• Don't tear it down first and ask afterwards. Settlement damage, cracks and uneven floors often only show up weeks or months later — and putting it right is many times more expensive than the original permit would have been.
• Don't trust that "the neighbour did the same thing". Houses get renovated differently, and an earlier renovation may already have shifted the load.
• Don't assume a thin wall is safe to remove. Thickness is a clue, not proof, and there are lightweight walls with hidden steel columns inside them.
• Don't skip getting it in writing. If you get a verbal green light on the phone, ask for an email. That email is what counts five years from now.

In short, the order that works is: floor plan → engineer's assessment → building authority → contractor quotes → work → update the register and keep the paperwork. Everything you move earlier in that order ends up cheaper.