ONS Building Materials Index: What It Means for Dorset Builders

The Office for National Statistics (ONS) has released its September 2025 Building Materials and Components Index, showing that while overall construction costs remain elevated compared to pre-pandemic levels, price pressures have eased across many key product groups.

After two years of volatility, supply chains are stabilising — a positive sign for builders in Dorset, Bournemouth, and across the South Coast heading into winter.

Brick and block prices steady, availability improving

The ONS data shows brick prices up just 0.6% month-on-month, with deliveries down around 5% year-on-year. Meanwhile, concrete block prices remained stable and deliveries rose by 2.7%, suggesting stronger supply at local merchant level.

Builders in Dorset report that stock levels are healthier than they’ve been since 2022, and lead times for standard concrete blocks and clay facing bricks have normalised across most of the South.

Timber costs drop further as demand cools

Imported softwood prices fell another 3% in the quarter, extending the downward trend that started last year. Slower new-build output and better global supply have eased timber costs, benefiting carpenters and roofers working on small developments and renovations in Bournemouth and Poole.

Hardwood and panel products remain slightly higher due to energy costs, but the overall timber market is far less volatile than it was 18 months ago.

Insulation and plasterboard edge higher

The only persistent upward movement came in insulation and plasterboard products, where energy and transport costs are still influencing prices. Manufacturers, including British Gypsum, have signalled modest increases heading into late 2025, though supply remains consistent.

Dorset builders are encouraged to check with local merchants early for lead times on specific insulation boards and acoustic products, especially for winter retrofit work.

Outlook for Dorset and the South of England

While national output has yet to return to 2019 levels, material cost stability is helping small builders plan projects more confidently.

• Shorter lead times mean fewer delays on small and medium-sized sites.

• More predictable pricing is easing pressure on fixed-price contracts.

• Energy-efficient upgrades (loft insulation, plasterboard renewals, and timber retrofits) continue to drive local demand.

For Dorset builders, this period of relative stability offers a window to lock in prices and schedule early-2026 projects with less financial uncertainty.