Expensive Parts in Building a Conservatory or Home Extension

If you're planning a conservatory, garden room, or any home extension, you know the excitement of seeing the design come together. But along the way, a few items will make your budget jump. Knowing which parts are pricey lets you plan ahead, avoid nasty surprises, and maybe shave off a few thousand pounds.

Big Ticket Items You Can’t Avoid

First up, the foundation. A solid base is non‑negotiable – a weak foundation can cause cracks, water ingress, and even make your insurance refuse a claim. Quality concrete, proper reinforcement, and professional installation often top the cost list. Expect around £80‑£120 per square metre for a good foundation, plus extra if you need specialist cement for repairs.

Next, glazing. Conservatories live or die by the glass you choose. Double‑glazed units are standard, but triple‑glazed, low‑E coatings, or insulated frames can add £200‑£400 per square metre. They improve energy efficiency, but the upfront price is steep.

Roofing and timber framing are another heavy hitter. Premium roof tiles, steel trusses, or engineered timber beams give strength and look great, but each comes with a higher price tag. A steel roof could cost double what a traditional felt roof does.

Finally, internal finishes – think high‑grade flooring, bespoke joinery, and designer kitchen or bathroom fittings. A hardwood floor or a stone countertop can quickly turn a modest budget into a luxury project.

How to Save Money on Costly Elements

Now that you know the pricey bits, here are a few ways to keep the bill reasonable. Start with the foundation: get at least three quotes, and ask if a thinner slab or a different mix can still meet structural requirements. Sometimes a lighter, high‑strength concrete can reduce both material and labour costs.

For glazing, consider double‑glazed units with a decent U‑value instead of going straight to triple‑glazed. The energy savings are still good, and you save a chunk of cash. If you need extra insulation, adding external shading or proper sealing can help without upgrading the glass.

When picking roof material, look for locally sourced tiles or metal sheets. Shipping costs can add up, so a regional supplier often means a lower price. Also, check if a simple pitched roof works for your design – it usually costs less than a complex curvy profile.

Finishes are where you can get creative. Vinyl flooring that mimics wood, ready‑made kitchen cabinets, or pre‑fabricated bathroom pods can give a high‑end look without the bespoke price. Mix and match – use premium material for the most visible areas and cheaper alternatives where it won’t be noticed.

Don’t forget to schedule your work wisely. Doing multiple tasks in one contractor visit saves travel time and reduces the markup on labour. And always read the fine print on warranties – a cheap product with a short warranty may end up costing more in the long run.

Bottom line: the expensive parts of a conservatory or extension are usually the foundation, glazing, roof structure, and high‑end finishes. By understanding why they cost what they do and applying a few smart strategies, you can keep the project exciting without breaking the bank.