The town
Aylsham sits between Norwich and the coast, and it made its money first from weaving linen and worsted, then from the market, and then from transport. A canal cut up from Burgh Bridge in the 1770s made the Bure navigable to the town, the Norwich turnpike followed twenty years later and reached Cromer in 1811, and the money that came with the traffic bought Aylsham the face it still wears. Pevsner, quoted in the district council's appraisal, called these the town's great years and said they explain much of its Georgian aspect.
A Georgian front in Aylsham is often the boom's face applied to whatever was already standing, and the appraisal is blunt about what sits behind it: very few timber frames are exposed in the town, and many more survive beneath the rendering and the brick facing. The material palette is Norfolk to the core, red brick and pantile, colourwashed brick under grey pantile, timber frame behind later fronts, and flint, and I have to get behind the elevation to find out which of them I'm dealing with.
The historic core around the Market Place is largely eighteenth and early nineteenth century. The conservation area drawn around that core in 1972 was extended in 1981 and again in 1990, so a house that feels well clear of the old town may still sit inside the line.
The ground
The ground under Aylsham changes within a few hundred yards. The British Geological Survey maps the town as a patchwork: glacial sand and gravel over much of it, a clay-bearing glacial till over much of the rest, and soft alluvium along the Bure. Sand and gravel drain freely and stay put. Till holds enough clay to move a little as it wets and dries with the seasons. Alluvium is soft and compressible. Which of them is under your house is a question about your address, and the answer can change between one end of a street and the other.
That matters because most of the older stock sits on shallow foundations, and a shallow foundation follows whatever it was built on. Where there's clay under a corner of the house, a mature tree drawing water out of it, or a leaking drain putting water back in, will show up as seasonal movement and cracking. Where the ground is sand and gravel, cracking usually has a different cause, and it's worth finding out which.
What tends to come up
- Movement and cracking, and the tree, drain or extension that is driving it.
- Lime and cement. Soft red brick repointed in hard cement spalls at the face. It's a repair problem that the repair caused.
- Pantile roofs. Cheap to lay, and frequently carrying a modern felt and batten that's been asked to do more than it can.
- Listed building and conservation consent. Broadland is the authority. Windows, roofs and rear extensions are where owners get caught.
Which survey
The older core, the listed stock and anything showing movement wants a Level 3 (Building Survey). A conventional, sound, twentieth-century house on the edge of the town is often well served by a Level 2 (Homebuyer) survey. Send me the address and I'll tell you which one it needs, including when the cheaper one will do.
Common questions
Why is there cracking in so many Aylsham houses?
Mostly because the older stock sits on shallow foundations, and a shallow foundation follows whatever the ground under it does. The ground here varies: the British Geological Survey maps glacial sand and gravel over much of the town, a clay-bearing till over much of the rest, and soft alluvium along the Bure. Where there's clay under a house, a mature tree drawing water out near a corner, or a leaking drain putting it back in, will show up as seasonal movement. Which of those you're dealing with is a question about the specific house, and it's what the survey is for.
Does that cracking mean subsidence?
Usually no. Most of the movement in Aylsham is old, seasonal and entirely liveable with. Some of it is progressive and expensive. The value of the survey is being told which one you're looking at, with the evidence set out. A report that hands you a referral to a specialist by default has skipped that work.
About defect diagnosis →Is my house likely to be listed?
There's a conservation area around the historic core, so in the centre it's a fair bet. The boundary was extended in 1981 and again in 1990, so a house that feels well clear of the old town may still sit inside it. Broadland is the planning authority, and its conservation area appraisal sets out what the constraints mean in practice. Windows, roofs and rear extensions are where owners most often get caught.
The brickwork is spalling at the face. Why?
Almost always because soft red brick has been repointed in hard cement. The mortar is stronger than the brick, so the brick face takes the stress and the moisture, and it blows. It's a defect the previous repair created, and the fix is to take the cement out and repoint in lime.