How long does cavity wall insulation last?

We had foam cavity wall insulation installed in our 1963 house about 40 years ago. We are concerned that it might have lost its effectiveness over the years as it is quite a cold house, but can’t find anything online to confirm or contradict this. If it has degraded over time, how can we improve the insulation of our house? Obviously it would be a tremendously difficult job to remove the foam insulation after all this time. Would a professional survey tell us? If so, from what sort of company?
Pam

Cavity wall insulation (CWI) is designed to last for the life of a house and in theory it should stay effective with no issues. But 40 years is a long time and it may have settled and slumped within the cavity. In some cases it can even deteriorate or be disturbed from building works.

It is likely that the foam insulation you had installed was urea formaldehyde foam insulation (UFFI), which is no longer installed in the UK. UFFI has been found to deteriorate with age, suffering from shrinkage, cracking and the integrity of the foam breaking down. This can then lead to reduced thermal performance, along with the added risk of moisture penetration into the property. The extent of the issues will include factors such as how well a property has been maintained and where it is in the country. A property with poor brickwork and mortar, in an area of high exposure to wind-driven rain, will be more at risk of encountering problems.

If your house does feel cold, then you are right to be concerned. I would recommend that you:

1. Arrange an inspection by an independent professional experienced in investigating CWI such as a chartered building surveyor, who will be a member of the Royal Institution of Chartered Surveyors (RICS).

2. Your surveyor can then assess the property and the insulation with an intrusive inspection. Cavity borescope cameras are normally used and even thermal imaging to pinpoint exactly where heat is escaping.

3. Depending on the condition of the insulation, they may recommend it should be extracted. Removing UFFI is a difficult process but not impossible and should be done by a specialist insulation extraction company. Ask it to provide case studies to ensure that it is suitably experienced.

4. The extraction of any CWI normally takes place over a number of days. The contractor should provide lots of photos and a sign-off document upon completion. It would also be prudent to have your own surveyor carry out quality checks both during the extraction and afterwards. This will also be of benefit if you ever come to sell your property.

After the extraction, you may decide to install new CWI. This would require an assessment of your property to see whether it is suitable by a qualified professional.
Ben Gardiner, chartered building surveyor, egertonsurveying.co.uk

How should I protect my carpet during building work?

What is the best way to protect my stair carpet from tradespeople’s traffic while I am having my bathroom refurbished?
Bob

When protecting your stair carpet during a bathroom refurbishment, there are several options depending on the level of work being undertaken. For light decorating jobs or removals, a self-adhesive lightweight polythene sheet such as Roll & Stroll, which costs £33.33 for a 100m x 0.6m roll from sealantsandtoolsdirect.co.uk, will suffice. For a more substantial refurbishment project, it’s worth investing in heavy-duty polythene (1,000-1,200 gauge) secured with 3M No Residue Carpet Tape, available from Screwfix at £7.69 for a 7m x 50mm roll.

For heavier building work where both the carpet and stairs need protection, there are two professional-grade solutions. The first is Correx stair protector, a 2-3mm corrugated plastic sheet that comes slit for easy folding over both tread and riser. This can be cut to size with a craft knife and costs £7.20 per tread from siteprodirect.co.uk, though do note there’s a £10 delivery charge.

The premium choice is Ram Board Stair Armor, made from slip-resistant recycled cardboard and measuring 2.4mm thick. These scored boards include clever interlocking flaps for complete coverage and feature grip strip backing anchors to prevent movement. A pack of six boards costs £34 including delivery from roofingsuperstore.co.uk. For the most secure installation, use Ram Board’s specialist seam tape, available from Toolstation at £11.99 for a 50m x 76mm roll.

For longer projects it’s worth checking the protection daily and adding doormats at the top and bottom of the stairs if trades are working in wet conditions. Whichever option you choose, ensure all edges are properly secured to prevent any tripping hazards.
Michael Holmes is a property expert for the Homebuilding & Renovating Show. Free tickets for an event near you can be claimed at homebuildingshow.co.uk/pr-sundaytimes. The next ones take place in Farnborough, Jan 18-19, and Birmingham, Mar 20-23

I’m looking for expert advice for my small garden as a beginner

My new year’s resolution is to plant up my flat’s walled patio garden. It’s not huge, it’s east-facing and there is a border 2.5m wide along the back wall and I’d say space for an additional four or five large pot plants near the patio set (table and chairs). I’d love some advice on what low-maintenance, beginner-friendly plants you would recommend for year-round interest. When should I look to plant up? I own the flat so I am happy to put up trellis etc if needed, and invest in plants that will last longer than one year.
Tamara, London

To give any garden year-round interest think “foliage”. While flowers come and go, a tapestry of evergreen leaves in different shades and shapes creates permanent interest and colour whatever the season. In courtyard gardens surrounded by brickwork, “architectural” specimens look stunning and one of the best is the castor oil plant, Fatsia japonica. A relative of ivy, it’s as tough as old boots and has large lobed leaves topped with a white inflorescence in autumn. The straight form is good but look out for the sparkling Fatsia japonica ‘Spider’s Web’ with silky white frosting on its leaves or the deeply scalloped and handsome Fatsia polycarpa ‘Green Fingers’.

Good for a corner away from paths (the leaves are spiky) is Mahonia ‘Charity’. The palm-like leaves are as green and glossy as the bonnet of a Bentley and in winter are topped with yellow blooms that will fill your courtyard with their lily of the valley perfume.

For wall cover and summer scent, plant star jasmine, Trachelospermum jasminoides. It will happily wind its way up and through a trellis and waft when you are sitting out on warm evenings.

One other evergreen I like to repeat-plant in pots and borders is pheasant grass, Anemanthele lessoniana. The leaves are wonderfully dynamic, moving in the breeze and burnishing from green to bronze in winter. They only live for a few years and turn up their toes once they reach the size and shape of a beanbag, but not before they’ve self-sown a few replacements.

Once the evergreens are in place, fill the gaps between and below with spring bulbs — snowdrops and daffodils are easy wins grown through ground-hugging perennials that slowly spread over years to cover the bare earth. Purple-leaved bugle (Ajuga ‘Burgundy Glow’) along with conserve-coloured Heuchera ‘Marmalade’ are good for this and both would also work well in your pots with the addition of the long-flowering cosmos. In small spaces the dwarf knee-high Cosmos bipinnatus ‘Sonata’ series in white and pinks are the ones to choose as they don’t flop, look fab in pots and flower from July to November. Buy from the garden centre in spring or sow your own on a windowsill indoors in March or April.
Toby Buckland is a presenter of Gardeners’ World; tobygardenfest.co.uk