Northallerton sits in DL6 and DL7, with the villages spread across both. Winters are proper winters. Frost is not a surprise, and a deck that was tight and damp in November is the one that shows it in March. Our team builds for that movement instead of pretending timber and fixings stay still.
What frost does to a deck
Frost hurts a deck that is wet. Water in a joint, in a check in the end grain, or in the soil around a shallow post, expands when it freezes. The board cups or the fixing works loose. The post lifts a fraction, and the deck that was level develops a rock. Dry timber in an open frame comes through a cold week with much less drama. The job is to let water leave before the night arrives.
Mud brushes off. A harsh wash that drives water into the joists, left for a freeze, does harm. Clear leaves before a cold spell. Snow is simpler if it can melt and go. A deck with no fall and no gaps holds the melt. That standing water is the frost problem, not the snow itself. We lay to a fall and we leave the gaps the board needs.
Posts and the ground
A post pinched into soft ground will heave. We dig a proper hole and concrete it so frost is not levering a spike. A dry spot and a wet corner on the same lawn are not the same hole. We do not print one frost depth for DL6 and DL7.
The BGS Geology Viewer is the regional map we look at first. The spade is the decision. If we hit fill, or a wet seam, the hole changes. A gravel base under an open frame helps water leave the surface under the deck. It must not be laid as a dam against the house. The wall keeps its gap. Rain and meltwater fall through that gap instead of sitting on the sill.
The flood map for planning matters where a plot is low and stays wet, because wet ground freezes harder on the frame. We do not publish zones. An ordinary town garden in DL6 can be drier than a village lawn in DL7 that never dries between rains. The exposed decks page is about the wind that often arrives with this cold. The two belong together, and they are not the same fix.
Gaps that allow movement
Boards shrink in a dry cold week and swell when a thaw brings rain. A deck screwed tight in the wet, with ends butted hard, will split or buckle when the weather turns. We leave a gap at the ends and between the boards, and we fix so that movement has somewhere to go. The gap is part of the build. It is also how meltwater gets off the surface.
Every cut end is sealed. Oil, if you use it, belongs on the ends as well as the face. A frame set too tight still suffers in a frost, whatever the board. Room to move is the point.
A squeak after a thaw is a fixing to look at. Where a fall could be more than about 600 mm, the guard has to stay sound through the winter.
DL6 and DL7 are not the same garden
DL6 takes in much of the town and some of the northern side. DL7 takes Romanby, Yafforth, Ainderby Steeple and other villages to the south and west. The frost falls on both. The gardens do not respond as one. A sheltered yard behind the town dries slowly and stays cold. An open Yafforth lawn freezes hard, thaws in the wind, and wets again. A Romanby close may be calmer than either. We ask which you have.
Planning rules do not relax because it freezes. The Portal's usual house starting point remains about 30 cm above the existing ground. Frost heave is not an excuse to build higher without saying so. North Yorkshire Council is the authority. Listed grounds sit outside the ordinary house allowances. Planning Data shows the conservation areas.
When you ask for a quote, say whether the garden holds water in winter or sheds it, and whether it is open to the fields. We will set the posts for the ground we dig, leave the frame able to dry, and tell you what to clear before a cold week. We will not call the deck frost-proof. We will call it built so frost has less to work on.
Questions people ask about frost and boards
Do you use one post depth for the whole area?
No. A wet corner and a dry one need different holes. We concrete the post deep enough that frost is not lifting a shallow fixing, and we decide that from the ground, not from a stock figure.
Should I cover the deck all winter?
A cover that stays damp does more harm than the frost. If you cover it, take the cover off when a dry day arrives. Leaves and standing meltwater are the things to clear.
Why are there gaps between the boards?
So the boards can move and so water can leave. A deck tightened in wet weather with no gaps is the one that splits or holds ice. The gap is deliberate.
Is DL6 kinder than DL7?
Not as a rule. Town shade stays damp. Open village plots freeze and thaw in the wind. Tell us which garden you have. The sky is shared. The lawn is not.