This guide is about the height test we use on Middlesbrough gardens. It is not a decision from the council. The council decides. We measure, and we tell you what we think the tape means.
What the height test is asking
Stand a ruler on the soil. Touch the top of it to the deck you would walk on. If that ruler reads more than 30 cm anywhere, the ordinary householder path has run out. An application is the usual next step.
The door threshold is a different problem. You still need a safe step down from the house. That step is not the planning measurement. People mix the two up. We keep them apart in the notes.
The test is about a raised platform. A few boards set low, with the frame clear of the clay, often stay inside it. A deck built to hold a flat seat on a falling garden often does not. Both can be good decks. Only one is the simple case.
The Planning Portal page is the public wording. We follow it, then we look at the garden.
Where we put the tape
We take several readings. One near the house. One in the middle. One at the outer edge. Clay settles into hollows. A single reading in the high spot will flatter the job.
On a slope the outer corner fails first. The boards are level. The ground is not. The gap grows as you walk away from the door. That is the whole point of a raised deck, and it is also why the application appears.
Joist depth uses up the gap. A deep joist, a bearer and a board can spend most of 30 cm before you have any air. If you want to stay under the line, say so at the start. We may need a slimmer frame, or we may tell you the line cannot be kept. Pretending is worse than an application.
Shade does not move the number. A dark yard and a sunny one are judged the same way. An alley does not move it either. Tight access changes the build. It does not change the ruler.
The rest of the householder tests
Height is the test people hit. It is not the only one. The deck, together with sheds and other garden buildings, should not cover more than half the garden. A small terrace yard can fail that while the deck still feels modest.
The deck should sit behind the front wall of the house. A platform in the front garden, facing the street, is a different case. We say that on the visit if the only sunny spot is at the front. Many Middlesbrough streets have the sun on the street side. The rule does not bend for that.
Flats and maisonettes are outside the householder rules we are describing. If the home is not a single house, we stop and point you to the council before we design a frame. The clay is the same. The paperwork is not.
An application is a set of drawings and a wait, not a reason to drop the deck. We mark heights on a simple plan.
Conservation areas, listed houses and clay
A conservation area can tighten what is allowed, especially at the side of a house. Middlesbrough has several. Check the address on the conservation-area map. Do not rely on the estate name. Boundaries stop in the middle of ordinary-looking streets.
A listed house is stricter again. Work in the grounds can need consent even when a neighbour's deck would not. We ask. If you are unsure, the council list settles it. We do not discover it after the posts are in.
Clay still has to carry the deck if the deck is allowed. A planning yes does not firm up soft ground. Posts and pads keep the frame off the soil. Water needs a way past the house wall. We do not block air bricks, and we keep the boards from bridging the damp-proof course.
Alleys matter at build time. Longer posts and bags of concrete use the same narrow entry as the boards. We plan that in the quote. If you want more than one level, see raised decking. Each level has its own reading. The highest outer edge comes first.
Your questions
Where do you measure the 30 cm?
On the soil, up to the walking surface, in several places. The biggest gap is the one that counts. The step at the back door is recorded too, but it is not the planning test. On clay, we do not measure from a soft mound that will be trodden flat.
Does shade or a narrow alley change the allowance?
No. Shade changes the board and the grip. An alley changes how we carry posts and concrete. The 30 cm figure stays. If a lift into the light would cross it, we tell you before you choose that lift.
What if the house is in a conservation area?
We look the address up. Inside a conservation area, side decks are often outside the ordinary allowance. A rear deck can still be the simple case if the other tests are met. We do not promise that from the street name. The map is the check.
Can you still build a deck that needs an application?
Yes. Many sloping Middlesbrough gardens need one. We set the heights out clearly, name the council, and wait for the decision before we build. The quote can include that drawing work so it is not a surprise later.