Facade work: render, cladding and external wall insulation

Hollow-sounding patches, cracks and blown areas of render can often be cut out and patched, but matching texture and colour on pebbledash or roughcast is difficult, and the repair usually shows. When large areas are loose, stripping back to the masonry and re-rendering is the longer-lasting answer. Taking pebbledash off can damage the face of the bricks underneath, so removing it to reveal brickwork rarely looks the way owners hope.

Masonry paint freshens a sound wall but does not fix a failing one. Cladding, in timber, fibre cement, tiles or brick slips on a carrier system, covers the wall rather than repairing it, and the wall behind still needs to be sound.

Solid brick and stone walls from before the widespread use of cavity walls were usually built and rendered with lime. They take in some moisture and let it dry out again. Hard cement render and impermeable masonry paint on these walls can hold moisture in, which shows up later as damp patches inside and frost damage outside. For a period house, ask whether the contractor works with lime render and breathable paints, and why they recommend what they do.

Houses with solid walls lose a lot of heat through them. External wall insulation fixes insulation boards to the outside and finishes them with render or another cladding. It keeps rooms full size, but it thickens the walls, so window sills, downpipes, gas meter boxes, eaves and verges all have to be extended or moved. Those details are where poor installations fail, so ask how each one will be handled.

If the extra thickness would cross the boundary with a neighbour or project over the pavement, you need their consent or the council's agreement first. Installers in competent person schemes such as those listed on GOV.UK for wall insulation can self-certify the work. Insulation installed in homes is currently zero-rated for VAT, and low-income households may qualify for the schemes listed on this page, which fund solid wall insulation in many cases.

Painting and repairs do not need planning permission. Outside protected areas, cladding a house in England is usually permitted if the materials look similar to the existing walls. In a conservation area, a national park, an Area of Outstanding Natural Beauty or the Broads, you need planning permission before cladding with stone, artificial stone, pebbledash, render, timber, plastic or tiles. Listed buildings need listed building consent.

The Building Regulations normally apply once a quarter or more of an external wall is re-rendered or re-clad, or its outer leaf rebuilt, and the wall's insulation then normally has to be improved. Walls close to a boundary may also need a level of fire resistance. In blocks of flats, the external wall is a fire safety matter for the building owner, and residents cannot simply choose their own cladding.

• survey of the existing wall: loose render, cracks, damp and the cause of any damage
• materials: render system, lime or cement, insulation type and thickness, finish and colour
• details at windows, sills, eaves, verges, downpipes and meter boxes
• scaffolding, licence for the pavement and protection of plants and paths
• Building Control or competent person scheme certificate
• guarantee, and whether it is backed by the system manufacturer or an insurer

Offrano is free for you. Once your phone number and email are confirmed, we offer the job, without your name or contact details, to rendering and facade firms in your area. One of them can buy it. It pays Offrano, the request is taken off the shop, and we email you the contractor's name, address and phone number before it sees your details.

It can happen that nobody buys the request; after 21 days it is withdrawn. You are never obliged to accept a quote. Offrano only checks that buyers are registered businesses, so for external wall insulation ask which scheme the installer belongs to and check it yourself, and for render ask to see work that is a few winters old.