Hartlepool has a lot of doors that were set close to the outside ground: estate houses, bungalows, and older houses with a replacement door in the original opening. A deck wants to feel level with that door. The wall wants the opposite. Water, wind-driven rain and the damp course all need the boards to stop short of the sill and to fall away. Our team treats that joint as a piece of the build, not as a trim at the end.
The sill and the board
The top of the deck should finish below the threshold, not hard against it and not above it. A board run into the sill traps grit and holds a puddle exactly where the door seal is. We leave a small gap, cover it in a way that can be cleaned, and make sure the gap is not a slot that funnels rain into the frame. The detail is quiet. You should step out without catching a toe, and the door should still shut without the board touching it.
On an open plot, rain is driven at the door. A fall away from the house, set in the frame, gives it a way to leave. The salt spray guide is the coastal version. Estate gardens are where the low sill is most common.
Air bricks and the damp course stay visible. A deck that buries them is a problem for the house, however neat the boards look. We measure from the sill and from those openings before we fix a joist height. If a previous surface has already bridged them, we will say so. We are there to build a deck, and we will not hide a damp detail under a new one.
Staying under the height limit
The Planning Portal allowance for a house includes a deck no more than 30 cm above the ground. A low threshold often makes that easy, because the door is already near the garden and the deck can stay low. The awkward case is the opposite of its name: a door that was renewed higher, or a garden that has been lowered, so the sill is now well above the soil. Chasing that sill with a tall platform can break the 30 cm line.
We keep the deck inside the allowance and use a step where the sill is high. Where the plot cannot be stepped, we explain the permission question before timber is ordered. Flats do not have the householder allowance. Tell us if the door belongs to one.
Half the garden still counts. A low deck can be large enough, with a shed, to cross that line on a short estate plot. We measure. Being close to the ground is not a permit to cover everything. Nothing goes forward of the front wall. In a conservation area, decking at the side of the house is not permitted development, even when it is low. Listed buildings have no permitted development for decking in the garden. The national map is the check.
Wind, rain and the frame
The frame under a low deck is shallow, and a shallow void is the one most likely to stay damp. We do not sit joists on the soil to gain a few millimetres at the sill. Posts and bearers hold the boards up. The edges stay open enough for air, including on the coast where drying depends on the wind getting underneath. A low deck with a solid skirt around it is a tray.
Water needs a lawn or a border to run to, not the neighbour's passage and not the air bricks. The flood map is for the postcode. The BGS viewer is the mapped ground. Trial holes still decide the posts.
Fixings near the sill see the worst of the drip. On a coastal plot they are specified for that, in the same spirit as a Headland frame. Inland of the sea wall, in a suburb such as Rift House, the load is less and the principle is the same: metal that lives in a wet joint should be fit for it.
What we measure on the visit
We measure the sill height above the garden at both jambs, because doors are rarely level to the ground. We look at the damp course, the air bricks, and the way the rain runs now. We note the passage width and the shed. Then we propose a deck height that the door can live with. If that height is inside 30 cm, the quote says so. If it is not, the quote says what the step is doing instead, or that an application needs a decision first.
Bring the postcode and, if you know it, whether the door was replaced. Ask for a quote. The visit is where the sill is understood.
Questions answered
Can the deck be flush with the door?
It should finish just below the sill, with a gap that does not trap water. Flush against the frame is how the joint stays wet.
What if the door is higher than 30 cm above the garden?
Then a deck built up to it is outside the usual allowance. We keep the deck low and step up, or we talk about permission before building.
Do estate houses have this problem?
Often, yes. The sill was set low, or a later door changed it. Estate gardens are full of both.
Does wind change the detail?
It changes how hard the rain hits the joint. The fall away from the wall matters more on an open plot than in a tight, sheltered yard.