Renovating a Period Property in Essex: What to Consider Before Work Begins

A modern house is designed to keep water out and to stay dry by being sealed. A pre-1919 house is designed to let water in and then let it out again. Solid walls with no cavity absorb moisture, and lime mortar, lime plaster, breathable finishes and generous ventilation let it evaporate away.

Almost every serious defect we are called to on a period property comes from somebody applying the first logic to the second kind of building. Seal it up, and the moisture that has always been in the wall can no longer leave — so it leaves through whatever is weakest instead.

Damp is the commonest reason people call us about a period house, and it is the area where most money is wasted — because the visible damage gets repaired and the thing causing it does not.

The pattern tells you a great deal. Damp in a defined area of a solid wall is almost always water getting in from outside. Damp spread evenly across a cold external wall, worst in corners and behind furniture, is usually condensation. A tide mark rising from the floor may be rising damp, but far more often it is a raised external ground level, a blocked air brick, a failed gutter or a cement render bridging the wall.

• Rainwater goods — overflowing gutters, split downpipes and a hopper discharging onto brickwork account for an enormous share of damp in old houses, and they are the cheapest thing on this list to fix.
• Ground levels — external ground raised above the internal floor, or a new patio laid over an air brick, will produce damp that no internal treatment will cure.
• Cement render and cement pointing — traps moisture in the wall and pushes it out through the face of the brick.
• Impermeable internal finishes — vinyl paper, plastic paints, gypsum over a solid wall.
• Blocked or lost ventilation — sealed chimneys with no vent, blocked underfloor air bricks, replacement windows with no trickle ventilation.

From our work

Period Drawing Room Restoration, Coggeshall, Essex

Failing plaster in a period drawing room at Coggeshall, in a corner that sat directly behind four external downpipes. The brickwork behind them was repointed and colour-matched and the area sealed first; only then was the internal plaster taken back to sound material and replastered in lime. Replastering without dealing with the outside would simply have reset the clock.

See the project

Lime, not cement

Cement mortar is harder than most historic brick. Moisture that would have evaporated through a soft lime joint leaves through the face of the brick instead, and in a frost the face spalls off. A spalled brick face cannot be put back — you can only cut out and replace the brick. Repointing an old wall in cement is the most expensive cheap decision available.

The same logic applies inside. Lime plaster on a solid wall allows the wall to release moisture; gypsum traps it and the damp reappears further along the wall a year later.

Windows

Original sashes and casements are usually repairable, and repair is almost always better value over the life of the building than replacement — the timber in a Georgian or Victorian window is slow-grown and far more durable than modern softwood. Draught-proofing an existing sash, with secondary glazing where the room needs it, gets most of the thermal benefit without the loss. On a listed building, replacement will need consent, and like-for-like is the only proposal likely to get it.

Floors

Suspended timber floors need their underfloor ventilation. Solid floors of brick, stone or lime ash were laid without a damp-proof membrane and were never meant to have one. Pouring a modern sealed slab into an old building displaces the moisture sideways into the walls, and the damp appears at skirting level shortly afterwards.

Insulation and heating

Loft insulation is nearly always worth doing and rarely controversial. Solid wall insulation is the opposite: it can be done well, but the build-up has to be designed for a breathable wall and the details at floors, joist ends and window reveals decide whether it works or rots the structure. Get that designed rather than bought off a shelf.

The thing that turns a period renovation into a bad experience is almost never the work itself. It is a budget set against assumptions, and then revised three times as the assumptions fail. The cure is to spend a little before anyone quotes.

• A full building survey by a surveyor experienced in traditional construction — not a mortgage valuation, and not a homebuyer report.
• Opening up. A handful of small, agreed openings into walls, floors and ceilings will tell you more about a building than any non-invasive survey. Budget for making them good again.
• A structural engineer's inspection wherever you intend to remove or alter structure, on the building rather than on the drawing.
• A measured survey, if the drawings you have are old or approximate. Old buildings are rarely square, and a design drawn on wrong dimensions produces variations later.
• Drainage. Below-ground drainage in an old property is frequently clay, frequently cracked and frequently not where the drawing says. A CCTV survey is inexpensive.
• Asbestos, in anything altered between roughly the 1950s and 2000 — artex, floor tiles, insulation board, cistern and flue components.
• A bat and nesting-bird check where roofs, voids or outbuildings are involved. Both are legally protected, and both stop work if they are found after it has started rather than before.

If the building is listed, assume internal work needs listed building consent and let someone confirm otherwise. If it is not listed, three things still catch people out:

• Conservation area — demolition and tree work are separately controlled, and materials and window design come under closer scrutiny.
• Article 4 directions — withdraw Permitted Development rights street by street. Your neighbour's experience is not evidence about your address.
• Party Wall etc. Act 1996 — engages on far more than people expect, including cutting into a party wall, inserting a beam, underpinning, and excavating within three or six metres of a neighbour's foundations depending on depth. Notice periods are one or two months, so it is worth identifying early.

Building Regulations apply to a period building too, though the energy efficiency requirements are applied with regard to the character of a historic building — the aim is the best reasonable improvement without causing harm, rather than new-build numbers.

You can usually stay in the house through a single-room or single-storey project. You usually cannot through a whole-house renovation where services are being replaced. We would rather tell you which applies at quotation stage than after you have committed, because it affects your costs as much as ours.

Where you are staying put, the protection matters as much as the work: access routes covered from the front door, work areas sealed where practical, furniture moved and sheeted, and the site left clean at the end of the day. It is your home before it is our site.

• Understand how the building handles moisture before you specify anything.
• Treat damp as a symptom. Fix the cause outside before repairing the damage inside.
• Lime where lime was, and be suspicious of anything that seals a solid wall.
• Repair windows rather than replace them where repair is possible.
• Pay for surveys and opening up before you set a budget, not after.
• Check the designations even if the building is not listed.
• Hold a contingency that means a surprise is an inconvenience.