Frequently asked questions

Many smaller projects fall under permitted development, which means they can go ahead without a full planning application, provided they stay within set limits. For a detached outbuilding or garden room, the main conditions are broadly that it is single storey, sits to the rear of the house, and that all outbuildings together cover no more than half the land around the original house. Height is limited too: a maximum overall height of 3m for a flat or mono-pitched roof, or 4m for a dual-pitched roof, with eaves no higher than 2.5m — and no more than 2.5m anywhere within 2m of a boundary.

These rights do not apply to listed buildings, and they may be restricted in a conservation area, in the New Forest National Park, or by an Article 4 direction. A garden room also cannot be used as separate sleeping accommodation under permitted development. Because the rules turn on detail, we always recommend confirming your position with the local planning authority before work begins, and we are happy to help you do that.

If your home is listed (Grade I, II* or II), you will usually need Listed Building Consent for any work that affects its special architectural or historic interest — and the listing covers the whole building, inside and out, not just the part named in the entry. Replacing windows, altering a fireplace, removing an internal wall, or re-rendering can all require consent, and so can routine-sounding jobs if they touch historic fabric.

This is worth taking seriously. Carrying out work that needs consent without it is an offence, there is no time limit on enforcement, and the responsibility passes to whoever owns the building. We have long experience of working sympathetically on listed and period homes, and we are glad to work alongside your local authority conservation officer to get the right consents in place before anything begins.

Old solid-wall buildings have no damp-proof course or cavity, so they are built to breathe — moisture moves into the wall and then evaporates away again. Lime mortar, render, plaster and limewash are vapour-permeable, so they let that moisture escape rather than trapping it.

Modern cement is hard and largely impermeable. On an old wall it holds moisture inside, where it has nowhere to go. Cement is also rigid, so it tends to crack as the building gently moves, and water then gets in behind it and is held there. Lime is softer and more flexible, so it works with an old building rather than against it.

Cob is an earth-based wall, and its great enemy is trapped water. The problems we see most often are:

• Hard cement render applied over the cob, which holds moisture in and slowly saturates the earth behind it.
• Damp, rising or penetrating, because the wall can no longer dry out.
• Cracking where rigid materials cannot flex with the wall.

In severe cases, saturated cob can soften and slump. The remedy is almost always to remove inappropriate cement, repair the cob with matching earth-based material, and finish in breathable lime so the wall can dry again. The old saying holds true: cob needs a good hat and a good pair of boots — a sound roof above and a dry base below.

First, resist the temptation to seal it with waterproof coatings or chemical treatments. On a breathable building these usually make damp worse, because they trap moisture in the wall rather than letting it out.

Damp in older homes is very often the symptom of something practical: cement render or modern paint stopping the wall breathing, a blocked gutter or downpipe, high external ground levels bridging the wall, or a plumbing leak. The sensible approach is to find the cause first, let the wall breathe again with lime, and put the simple things right. We are always happy to come and take a proper look before anyone reaches for a quick fix.

Yes — but the materials matter enormously. The key is to use breathable, vapour-permeable insulation, such as wood fibre, that lets the wall carry on managing moisture. Materials of this kind can take up and release water vapour without the wall becoming saturated.

What is best avoided on a solid-wall building is plastic foam board and impermeable vapour barriers, and dot-and-dab fixing that leaves voids behind the lining. These can trap moisture against the wall and lead to damp and decay. Done thoughtfully, with the right detailing and ventilation, a breathable approach makes an old home warmer and more comfortable while keeping it healthy.

Green oak is freshly sawn, unseasoned timber, and it is the traditional material for timber framing. As it dries in place it shrinks across the grain and develops surface splits called shakes. This is entirely normal and expected, and it does not weaken the frame.

In fact, traditional framing allows for this movement. The joints are cut and pegged so that as the timber shrinks the joints tend to tighten rather than loosen. A little creaking, some gentle movement and the odd shake are simply part of living with an honest oak frame.

Because green oak moves as it dries. With traditional mortise-and-tenon joints and oak pegs, the timber shrinks onto the joint and the peg holds it firm. A technique called draw-boring, where the peg holes are deliberately offset, actually draws the joint tighter as it is assembled.

Metal bolts can behave the opposite way. As the surrounding oak shrinks, the timber can pull away from the steel, so bolts work loose and joint shoulders open up. Seasoned hardwood pegs move in sympathy with the frame, which is one reason a well-cut pegged joint can last for centuries.

It usually begins with a conversation and then a visit, so we can see the building, understand what you would like to achieve, and give you honest, practical advice. For more involved work we offer a consultancy visit. There is a fee for this, but if you go ahead with the work, that fee is deducted from your final invoice.

From there we can advise on the right approach, any consents you may need, and the likely shape of the project before anyone commits to anything.

We are based in Edmondsham in East Dorset and work across Wiltshire, Hampshire, Dorset and the New Forest, up to around 50 miles from Edmondsham. That includes Wimborne, Cranborne, Verwood, Ringwood, Fordingbridge, Ferndown, Bournemouth, Poole, Salisbury and the surrounding villages.

If you are a little further afield and have a building that suits our way of working, do get in touch and ask — we are always happy to discuss it.

The best first step is simply to call us on 07711 360 698 or email office@colinclarkbuilders.co.uk with a little about the building and what you have in mind. Photographs are always helpful.

For most heritage and period work we like to see the building in person before quoting, because every old house is different and sound advice depends on understanding what is actually there. We will then set out clearly what we propose and what the work is likely to involve.

We are a traditional building firm, established in 1978 and incorporated as Colin Clark Builders Ltd in 2002, with more than forty years' experience. Our work centres on older and historic buildings, including:

• Cob wall construction and repair
• Lime mortar, render, plaster and limewash
• Green oak and chestnut timber framing
• Restoration of older and listed buildings
• Eco builds, extensions and outbuildings such as garden rooms
• Brick, flint and stone masonry
• Breathable insulation and sustainable heating

Our craftsmen include head carpenter Andy Shervington and lead joiner Dan Timmins, who heads our own joinery workshop in Edmondsham, and founder Colin Clark co-produced a cob buildings advice publication with the New Forest conservation team.