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ServiceCellar and basement tanking in Lincoln
Lincoln is a city with cellars. Victorian terraces and townhouses were routinely built over coal cellars, and the older buildings of the historic core carry below-ground spaces that have been there for centuries. Most were never meant to be dry rooms. They can be made into them.
What Lincoln cellars are up against
A cellar wall is a retaining wall holding back permanently damp ground, built long before modern waterproofing existed. What that ground is doing depends, once again, on which half of Lincoln the house stands in.
Downhill, cellars sit close to the water table on low river land beside the Witham, ground that stays workable only because the Sincil Dyke and the city's drains keep it that way. After prolonged rain, some cellars here take standing water, and most stay humid all year. Uphill, the ground drains freely through the limestone, but rain moving down through the ridge finds its way along joints in the rock, and where the limestone meets the impermeable clay beneath, water emerges as springs. The spring line along the foot of the Edge is precisely where many older buildings stand, so an uphill cellar can be wet in a different way: dry for months, then streaming during a wet winter.
Two ways to make a cellar dry
Cementitious tanking
A waterproof render and slurry system applied directly to the walls and floor, physically holding moisture back. Suited to cellars with modest moisture loads and sound masonry, it is generally the cheaper option, but it must be applied to a properly prepared substrate and it asks a lot of the wall, since water pressure behind it has nowhere to go.
Cavity drain membrane
The approach most modern below-ground conversions use. A studded membrane lines the walls and floor, accepting that water will arrive and channelling it behind the membrane to a drainage channel and sump pump that carries it away. It handles higher water loads, copes with the wet-winter surges that spring-line properties see, and is kinder to historic fabric because the original wall is left to breathe behind the membrane.
| Tanking | Cavity drain | |
|---|---|---|
| Best for | Storage cellars, modest damp | Habitable rooms, wetter ground |
| How it works | Blocks water at the wall face | Collects and pumps water away |
| Ongoing needs | None once cured | Sump pump servicing |
| Relative cost | Lower | Higher |
Storage or living space, decided honestly
Not every cellar justifies conversion money. If the goal is dry storage, improved ventilation, a tidy tanking job and attention to outside ground levels may be all that is needed. If the goal is a habitable room, building regulations on ceiling height, escape, ventilation and insulation come into play, and the waterproofing design needs to be right first time, because everything else is built on top of it. The specialist will tell you which side of that line your cellar sits on before you commit to either.
A cellar that floods during prolonged wet weather is telling you about water pressure, not just damp. Painting a waterproof coating over it usually moves the water somewhere else, often up into the walls above. Below-ground waterproofing is a design job, not a decorating job.
Getting a quote
Tell us what the cellar does now, what you want it to do, and how wet it gets at its worst. The vetted specialist will inspect, recommend tanking or cavity drainage on the evidence, and give you a written quote for the design that fits.
A cellar you avoid going into?
Below-ground space is the cheapest floor area a Lincoln house has. Find out what making it dry would actually involve.