Knocking a wall out is the easy bit. The bit that catches people out is selling the house five years later and the buyer’s solicitor asking for the steel calcs and the building control certificate.

Every knock through we do in St Helens comes with both.

What a knock through costs

A kitchen diner knock through we did in Rainford, St Helens came to £3,700. That included the engineer-specified steel and making good the whole area afterwards.

An integral garage conversion in St Helens with a doorway knocked through into the house came to £12,700. The garage conversion page has the full breakdown.

Every job is priced after we’ve seen it, because the wall, what’s above it and how far it spans all change the steel. The price we agree is the price you pay.

Steel calcs and building control

Take out a wall that holds up the floor or roof above and you need a steel beam sized by a structural engineer. Those are the steel calcs: the engineer’s sums showing the beam will carry the load.

Building control then inspects the work and signs it off. That certificate is what a buyer’s solicitor asks for. Skip it and it comes back when you sell.

We arrange the engineer, the calcs and the inspections. You get the paperwork at the end.

The knock throughs we do

Kitchen diners. Opening the kitchen into the dining room for one open-plan space. On this single storey extension the steel went in first, then the roof joists, then the lower wall came out.

Bi-folds and glass. Opening up a rear wall for bi-folds or glass panels. On this kitchen diner we swapped the back wall for glass to make the most of the garden.

Garage to house. A doorway from a converted garage into the hall or living room. Usually in and out in two days: lintel in, wall down, new door and casing fitted, rubbish gone. We did one into the living room in Windle in October. Here’s week one.

Extensions. Knocking through into a new extension, like the double knock through on our side extension in Billinge.