Knowledge
Guides & advice
Practical, accurate guidance on cob, lime, oak and listed buildings — written by craftsmen who work on them every day.
Cob & earth walls
How to repair a cob wall
Repair a cob wall by first diagnosing the damp causing the decay, then keeping it dry with a sound roof and dry base ("good hat and good boots").…
Read the guideBuilding with cob today: new cob & natural building
Cob is a monolithic earth-and-straw walling material: clay subsoil, sand, fibre and water built up in layers on a stone plinth. New-build cob is…
Read the guideWattle and daub: what it is and how to repair it
Wattle and daub is a traditional infill for timber-frame panels: a lattice of riven oak laths or woven hazel (the wattle) carrying an earth-based…
Read the guideLime, render & plaster
Lime vs cement render: why cement damages old buildings
Cement render is too hard and too impervious for old solid-wall, cob and stone buildings. It traps moisture inside the wall, which then escapes…
Read the guideUnderstanding lime: NHL vs non-hydraulic (lime putty)
Building lime falls into two families: non-hydraulic (lime putty/air lime, CL 90) sets purely by carbonation and is soft, breathable and ideal for…
Read the guideLime mortar mixes and ratios explained
Lime mortar is specified by binder type — non-hydraulic lime putty, or natural hydraulic lime graded NHL 2, 3.5 or 5 — gauged with sand at roughly…
Read the guideHow to repoint with lime mortar
Repointing replaces failed surface mortar in masonry joints. Rake out old, soft or cement pointing to roughly 2 to 2.5 times the joint width without…
Read the guideLime plastering a cob wall: a step-by-step guide
Lime plastering a cob wall is best done as a breathable, three-coat system over a properly prepared background. First strip back any cement render…
Read the guideDamp, breathability & decay
Breathability and damp in old buildings
Old buildings have no damp-proof course; instead, their solid walls of soft brick, stone, cob, lime mortar and lime plaster absorb moisture and let…
Read the guideDamp in old houses: rising, penetrating or condensation?
Old houses suffer three damp types: rising (groundwater wicking up walls), penetrating (rain entering through defects) and condensation (warm moist…
Read the guideWoodworm, rot and timber decay in old houses
Timber decay in old houses is driven by damp, not bad luck. Furniture beetle, deathwatch beetle, wet rot and dry rot all need moisture; dry timber is…
Read the guideCracks in old house walls: when to worry
Most cracks in old walls are harmless seasonal movement or long-settled shifts, especially fine, stable, vertical hairline cracks. Worry when cracks…
Read the guideLimecrete and breathable floors in old buildings
In a breathing old building, a sealed concrete floor with a damp-proof membrane traps ground moisture and diverts it sideways into the walls,…
Read the guideTimber, oak & joinery
Green oak timber framing explained
Green oak is freshly felled, unseasoned oak worked while soft. As it dries in place it shrinks across the grain (up to about 7.5%), tightening…
Read the guideRestoring oak beams (and why not to sandblast or black them)
Don't sandblast or black-paint old oak beams. Heavy abrasion strips centuries of patina and roughens the timber; black gloss and bitumen look wrong…
Read the guideSash window repair, restoration & draught-proofing
Original timber sash and casement windows can almost always be repaired rather than replaced. Rot, broken cords, draughts and paint-sealed sashes are…
Read the guideReclaimed materials: matching brick, tile, timber & stone
Reclaimed brick, tile, slate, timber and stone let you repair period and listed buildings honestly, matching the original size, colour, texture and…
Read the guideRoofs, chimneys & thatch
Thatched roofs explained: types, lifespan & owning a thatched home
A thatched roof is a living, breathable covering that protects the cob and timber beneath. The three UK materials — long straw, combed wheat reed and…
Read the guideRoof repair & re-roofing for period and listed homes
On a period or listed roof, repair sound slates and tiles wherever possible rather than stripping the whole roof. When re-roofing is unavoidable,…
Read the guideChimney repair, repointing & leadwork on period homes
Period chimneys fail when failed flashings, hard cement repointing and cracked flaunching let water in. The right approach uses breathable lime…
Read the guideFlint walls: building, knapping and repair
Flint walling is the defining vernacular of Cranborne Chase and East Dorset. Built with field, beach or knapped flint and bound in lime mortar (never…
Read the guideWarmth & running costs
Insulating an old house without causing damp
Old solid-wall, cob and timber-framed homes need to breathe. Standard PIR foam and plastic membranes trap moisture inside porous walls, causing damp,…
Read the guideEnergy efficiency for period & listed homes (and EPCs)
You can make a period or listed home warmer without harming it by working with its breathable fabric, not against it: draught-proof first, add…
Read the guideUnderfloor heating in old and period homes
Yes — underfloor heating works beautifully in old and listed homes, but only if it is built breathable. That means a limecrete floor over…
Read the guideOpening up an inglenook fireplace (and bread ovens)
Behind a 20th-century blocked-up fireplace you may find a generous inglenook, its bressummer beam, bread ovens and salt cupboards. Open it up…
Read the guidePermissions, money & buying
Listed Building Consent explained
Listed Building Consent is the formal permission needed to demolish, alter or extend a listed building in any way that affects its special…
Read the guideConservation areas explained: what you can and can't do
A conservation area is an area of special architectural or historic interest, designated by your local council, whose character the law protects.…
Read the guideVAT and listed-building & period-home work explained
VAT on listed-building and period-home work is often misunderstood. Since 1 October 2012, approved alterations to listed dwellings are standard-rated…
Read the guideBuying a period, listed or cob home: a survey checklist
Period, listed, cob and thatch homes hide costs a standard mortgage valuation never finds. Before you buy, commission a specialist Level 3 survey…
Read the guideBats & protected species in old-building work
All UK bats and their roosts are strictly protected by law, whether or not bats are present, and nesting birds are protected too. Before roof, loft…
Read the guideConservative repair: the SPAB approach to old buildings
Conservative repair is the conservation philosophy set out in the 1877 SPAB Manifesto: protect and repair an old building rather than restore it to a…
Read the guideChoosing a heritage builder: questions to ask
Choosing a heritage builder means checking for the right knowledge, not just a good price. Ask about lime and breathable repair experience,…
Read the guideMaintaining a period home: a seasonal checklist
A period home stays sound through small, regular tasks, not big interventions. Clear gutters and check render and pointing in autumn; inspect roofs,…
Read the guideCosts, process & questions
Heritage building cost guide
Typical UK price ranges for cob, lime, oak and listed-building work, to help you budget.
View cost rangesCaring for a cob & lime building
An owner’s guide to why cob must breathe, what damages it, and how it is correctly maintained.
Read the guideHow we work
How a heritage or listed-building project runs with us, step by step.
See our processFrequently asked questions
Planning, Listed Building Consent, lime vs cement, damp, green oak and more.
Read the FAQHave a question we haven't covered?