RICS Chartered Surveyors in Skipton

Craven ground: limestone, faults, sinkholes and radon

Skipton sits on one of the most abrupt geological boundaries in England. The Craven Faults run across the district, and they separate the massive Carboniferous limestone of the Dales to the north from the shales, sandstones and thinner limestones to the south. The consequence for a buyer is that two houses a few miles apart can be standing on ground that behaves in completely different ways, and neither the estate agent's particulars nor a mortgage valuation will mention it.

Limestone is soluble. Rainwater that has picked up a little acidity dissolves it slowly along joints and bedding planes, opening fissures, then voids, then in places a cave system. Where the soil cover above such a void is thin or is washed down into it, the surface can subside, sometimes gradually and occasionally all at once. Craven is well supplied with the evidence: shake holes pocking the fields, streams that vanish into the ground and reappear somewhere else, and depressions in pasture that follow lines nobody put there. A property does not have to be sitting over a cavern to be affected. Localised settlement over a soft filled hollow does the damage just as effectively, and it shows as cracking that is worse at one corner, a drive that dips year on year and drains that keep breaking in the same spot. Where what we see points that way, the report tells your solicitor to obtain ground stability data for the site rather than leaving you to hope.

Radon deserves proper attention here and rarely gets it. Parts of the Dales and the ground around Craven are designated radon Affected Areas, meaning a measurable proportion of homes exceed the action level for this naturally occurring radioactive gas, which seeps out of the rock and accumulates in enclosed ground floor space. Limestone country with fissured rock beneath it, and the mineralised ground associated with the faults, is precisely the setting where it occurs. The practical points are these. A survey cannot measure radon, because measurement means leaving detectors in the house for three months to average out the seasonal swing. A radon report for the postcode is inexpensive and your solicitor should obtain one. If the property is in an Affected Area and the ground floor has been replaced, or an extension has been built, protective measures should have been incorporated, and where we can see no evidence that they were we say so. Remediation in an existing house is usually a sump and a small fan, which is neither ruinous nor complicated, but it is far better established before exchange than discovered afterwards.

Water is the fourth part of the ground story. The Aire rises above Gargrave and runs down past Skipton towards Cononley, and property on the valley floor at Cononley and along the washlands has taken water in the past, while Eller Beck and the smaller becks through the town itself have surcharged in heavy rainfall. On limestone, groundwater does something extra: it moves through fissures rather than percolating evenly, so a spring can appear in a cellar after a wet week and disappear again. Where the setting calls for it the report asks for a flood search, and in any low lying property we are looking for replaced floors, plaster renewed to a consistent height and skirtings newer than the house around them.

Barns, farmsteads and the services that come with rural property

The converted barn is the signature purchase in Craven and the one that produces the longest reports. A field barn or a farmstead range was built as a single open volume with rubble walls, minimal footings sitting more or less directly on the soil or on rockhead, a roof carried on a handful of heavy trusses, and no requirement whatever to be warm, dry or level. Turning it into a house asks it to be all three. Most conversions here happened between the 1980s and the present, and the quality varies more widely than in any other category of property we inspect.

The structural questions come first. Wide openings were formed in rubble walls to take glazing, and those openings need a lintel with a proper bearing and padstones to spread the load: where that was skimped the stonework above drops and a crack climbs from the corner of the frame. New floors were inserted into a volume never designed to carry them, so we look at how the joists are supported, whether the wall was strengthened or simply drilled, and whether the ridge and purlins have moved since. Original roof trusses were frequently cut about to gain headroom in a mezzanine. Timber lintels and bressumers over former cart and byre openings are often still in place, embedded in damp masonry, and wet rot in a beam like that is not visible until somebody opens up the plaster.

Moisture is the second theme. A rubble wall a metre thick has no damp proof course, and it stayed sound for centuries because it was cold, ventilated and unheated. Insulate it internally, seal the floor, fit tight joinery and heat it, and the moisture that used to leave through the inner face condenses within the construction instead. The joist ends and wall plate sit in the worst of it. Rendering the outside in cement, or coating it in a modern masonry paint, makes matters worse rather than better by closing off the last route out. We take moisture readings, but we read the building first and the meter second, because a meter on a rubble wall tells you what is in the plaster, not what is in the stone.

Then there are the services, which is where rural buyers are most often caught out. A large number of properties around Gargrave, Cononley, Embsay and the villages up Wharfedale and Airedale are not on mains drainage. They run to a septic tank or a package treatment plant, and since the general binding rules changed a septic tank discharging directly to a ditch, beck or river has had to be replaced or upgraded, which is the buyer's problem the moment the deeds change hands. A drainage field needs the right soil and enough space to work, and fissured limestone ground is poor at providing either, since effluent can travel through fissures instead of being treated by the soil. We ask what the system is, where it discharges, when it was last emptied, who else is connected to it and whether any consent or registration exists. Private water supplies from a spring or borehole raise the same style of question: recent sampling, the state of the storage tank, where the pipe runs and whose land it crosses, and whether anything in writing protects your right to it.

Defects we see most in Skipton and Craven homes

The pattern of findings here is rural and geological rather than industrial, and these are the ones that appear most often in our reports.

• Localised settlement over solution features and soft filled hollows in limestone ground, showing as cracking concentrated at one corner, a drive that keeps dipping and drainage runs that fracture repeatedly in the same place.
• Septic tanks still discharging to a beck or ditch contrary to the general binding rules, and drainage fields that are undersized, waterlogged or laid in ground that was never capable of treating the outflow.
• Wide glazed openings formed in rubble barn walls with an inadequate lintel bearing or no padstones, with diagonal cracking running up from the head of the frame.
• Cement render and modern masonry paint applied over limestone and gritstone rubble, sealing the wall so moisture leaves through the internal finish and decays the plaster and skirtings instead.
• Properties in radon Affected Areas where a ground floor slab has been replaced or an extension added with no evidence that protective measures were incorporated.
• Private water supplies with no recent sampling record, untraced pipework crossing land in other ownership and storage tanks that have not been opened for years.
• Decayed timber lintels and bressumers over former cart and byre openings, carrying load while embedded in masonry that has been damp since the roof last leaked.
• Field walls, outbuildings and garden structures built with no real foundation, leaning or bellied, and left out of the maintenance of the house they belong to.

Buying in Craven: planning constraints, access and the right moment to instruct

Skipton draws buyers from the West Yorkshire cities and from further afield, and good property here goes quickly. Instruct the survey once your offer is accepted, before you fix your mortgage product, because on a rural purchase the findings can change the shape of the deal rather than just the price. A drainage system that has to be replaced, a barn conversion needing structural work or a water supply with no documented right attached to it all take time to resolve, and time is what you lose by waiting for the searches first.

Access has to be organised properly on a rural inspection and we arrange it through the agent in advance. On a farmstead we want the outbuildings unlocked, the roof space reachable, the tank lid locatable, the electricity and water isolators identified and somebody able to say where the boundary actually runs, since a stone wall and a title plan do not always agree in this district. Winter weather matters too. A single track lane above Embsay or towards Grassington can be impassable after snow, and a visit booked for a settled week is worth more than one hurried through in bad conditions.

Planning constraint varies sharply across a short distance. Skipton itself lies outside the Yorkshire Dales National Park, but Grassington and much of upper Wharfedale are inside it, where planning control is tighter, permitted development rights are more limited and the expectations for materials and detailing on any alteration are higher. The town has conservation areas covering the historic core and the canal, and listed buildings are numerous, from the castle and the High Street down to farmhouses and barns that carry a listing most owners are surprised by. The report records designation and flags alterations that look as though they required consent nobody can produce.

It is worth being clear about the arithmetic on an older Craven property. The average repair bill facing new home owners is around £5,750, and on a converted barn or an unmodernised farmhouse the sum our reports identify is regularly a multiple of it, because the work comes in indivisible lumps: a roof, a drainage system, a damp strategy, a set of windows. None of that is an argument against buying. It is an argument for knowing the number and the order the work has to be done in, which is what the report sets out.

When the report reaches you, ring the surveyor and talk it through. Where something needs to be quantified we can follow up with a structural engineer's report or a timber and damp report, so you go back to the seller with evidence rather than an anxiety.

Other surveys and valuations we carry out around Skipton

Besides Level 2 and Level 3 surveys, clients in Craven instruct us for structural engineer's reports where a barn conversion or a farmhouse is showing movement, timber and damp reports on rubble walled property and cellared town houses, and drone roof surveys where a long farmstead range or a steep town roof cannot be seen safely from the ground. Valuation work is a substantial part of what we do here: probate valuations, matrimonial valuations, private valuations for sales within a family, Help to Buy valuations and building insurance reinstatement assessments, which matter on stone property because rebuilding in matching materials to a conservation or listing standard costs considerably more than rebuilding in brick and tile.

We cover Gargrave, Embsay, Cononley, Sutton-in-Craven and Grassington from the same base, together with the farms and hamlets in the dales between them, and travel is included in the fixed fee so an isolated address does not attract an extra charge. On the commercial side we survey shops and offices in the town, agricultural buildings, workshops and let units, prepare schedules of condition before a lease begins, advise on dilapidations at the end of one and carry out commercial valuations and rent reviews. The complete list is on our Types of Survey page, and if your situation is not covered there, call and tell us about the property.