The short answer
If the building stands wholly on your own land, clear of the boundary, does not cut into a wall you share with your neighbour and does not need deep foundations next to a neighbouring building, the Party Wall etc. Act 1996 does not apply and you need no notice. Planning permission and building regulations are separate questions.
The three tests
Ask these three questions about your garden room, shed, garage or other outbuilding.
| Ask yourself | If yes | Notice |
|---|---|---|
| Will a wall of the building stand right on the boundary line? | You are building on the line of junction. Serve notice at least one month before you start. Your neighbour can consent to a wall shared on the line. If they do not, you can build wholly on your own land, at your own cost. | Section 1 |
| Will the building cut into, or bear on, a wall you share with your neighbour? | That is work to a party wall or party fence wall. Serve notice at least two months before you start. Minor fixings, such as plugs for a shelf, are generally not treated as notifiable. | Section 3 |
| Will you dig close to a neighbour’s building and go below the base of its foundations? | Within 3 metres and deeper than their foundations, or within 6 metres and cutting a line sloping down at 45 degrees from them. Serve notice at least one month before you start. | Section 6 |
A “building or structure” in the third test includes your neighbour’s garage, shed or masonry garden wall, not only their house.
Common garden buildings
| What you are building | Usually needs a notice? | Why |
|---|---|---|
| Timber garden room or shed on ground screws, pads or a shallow base, set in from the boundary | Usually no | It is not on the boundary, it joins no shared wall and it digs little or nothing. |
| Garden room on a concrete slab or raft | Usually no | Slabs are normally shallow. The question is whether you dig below the base of a neighbouring building’s foundations within 3 or 6 metres. |
| Brick or block outbuilding or garage with strip foundations on the boundary | Yes | A wall on the line of junction needs a Section 1 notice, and a deep trench near their building can need Section 6 as well. |
| Store or lean-to built against a masonry wall you share with a neighbour | Often yes | A lean-to usually needs a flashing cut into the wall, and cutting into or bearing on a shared wall is work to it. See Section 3. Standing beside the wall is not. |
| New masonry boundary wall | Yes, if it is on the line | A new wall on the boundary is a Section 1 matter. |
| Timber fence | No | A timber fence is not a wall. See fences and garden walls. |
| Swimming pool, hot tub pit or deep pond | Check | A deep excavation near a neighbouring building can reach Section 6. |
If you are not sure which row you are in, send us a sketch and we will tell you.
Other rules still apply
Planning permission, building regulations, covenants in your deeds, drains and tree roots are all separate from the Act. A garden room that passes every party wall test can still need planning permission or building regulations approval, depending on its size, height, position and use, so ask your local council.
Eaves, gutters and roof overhangs that reach over the boundary are a separate matter too. They can be a trespass over your neighbour’s land, so agree them with your neighbour first.
If you are the neighbour
If a garden room goes up right on your boundary and you received no notice, ask the owner whether any wall stands on the boundary line or whether they have dug near your foundations. A note of the date and photographs of your side now will help later. See what to do when work starts without a notice.
What to send us
A short email is enough:
- Photographs of the site and the boundary.
- A sketch or plan showing the building’s distance from the boundary and from your neighbour’s buildings.
- The type of base or foundation you plan, and how deep it will be.
- Whether anything will be cut into, or carried on, a wall you share.
We will tell you whether any notice is needed. If one is, we prepare and serve party wall notices for £70, with no VAT. Call us on 0800 999 1947 for a free first conversation.
Garden room and outbuilding questions
Do I need a party wall agreement for a shed?
Rarely. A shed on your own land, set in from the boundary on a shallow base, joins no shared wall and digs little. The three tests above are the check. If the answer to all three is no, the Act does not require a notice.
Does a garden room built right up to the boundary need a notice?
If a wall of it stands on the line where the two properties meet, yes. That is a Section 1 notice, served at least one month before work starts. If the whole building is set inside your own land, Section 1 does not apply, although the digging test may still matter.
Can my neighbour stop me building a garden room?
Not under the Act, unless a wall of it would stand across the boundary, which needs their consent. Objections to the building itself go to the council as planning matters. See can my neighbour stop my building work?
My neighbour has a garage near where I will dig. Does that count?
Yes. A neighbour’s garage, garden wall or outbuilding counts as a building or structure for the digging rule. If you will go below the base of its foundations within 3 metres, or cut the 45 degree line within 6 metres, a Section 6 notice is needed. A trial hole shows how deep their foundations are.
Do ground screws need a notice?
Usually not, because ground screws disturb very little soil. The depth test still applies if they will go below the base of a neighbouring building’s foundations within 3 metres, so check if you are close to one.