How much should you budget for a small house clad in sandwich panels?

Allow 96 m² of wall panels to cover the cutting schedule. Assume a roof surface of 100 m² and an order of 108 m² of roof panels. Use the roof pitch, overhangs and details to calculate the roof area. In a real project, assembly drawings determine the quantities. The extra material depends on the cuts and panel layout.

Assume roughly €42.87/m² excluding VAT for wall panels and €49.82/m² for roof panels. These are illustrative rates converted to euros. Using unrounded rates gives €4,115.41 for walls and €5,380.62 for the roof. The combined panel cost before rounding is €9,496.02 excluding VAT.

When comparing actual quotes, specify the core, thickness, facings, coating and required performance. A PIR insulation board with flexible facings serves a different purpose from a sandwich panel with steel facings. Confirm that the quoted product meets the specification before comparing prices.

Add €2,317.23 for flashings, seals and fixings, €3,939.30 for installation and €1,274.48 for transport and equipment, all excluding VAT. Including the panels, the envelope package comes to €17,027.03 excluding VAT. The primary structure, windows and doors are separate packages.

In an actual quote, itemise corners, plinths, eaves, ridge details and service penetrations. Additional openings or restricted access can increase labour costs. Establish whether delivery includes unloading and who pays if equipment stands idle. Quotes with similar totals may cover different work.

For the rest of the example, allow €17,379.25 for foundations and ground preparation, €11,122.72 for the frame, €8,805.49 for windows and doors, €23,172.34 for services, €24,330.96 for finishes and €9,268.94 for design and remaining site works. Together these items come to €94,079.69 excluding VAT before rounding the individual lines.

Including the envelope gives €111,106.73 excluding VAT before contingency. This is a budgeting exercise. Land and financing are outside its scope. For a real house, describe utility connections, plant, fittings and external works in enough detail to identify gaps or double counting.

A 10% contingency on the unrounded subtotal adds €11,110.67. The budget including contingency is €122,217.40 excluding VAT. The percentage is an assumption for this example. Uncertain ground conditions, unusual junction details or alterations to an existing building may warrant a different allowance. Link each allowance to a specific risk.

The amounts above exclude VAT. To find the amount payable, add tax according to the contracts and rules that apply to the work. Check supplies and services individually. Use separate columns for the net amount, tax and gross amount when comparing quotes.

Send each contractor the same quantities and requirements. Ask them to identify exclusions, timing, how changes are priced and when payments fall due. Distinguish fixed-price work from items charged on measured quantities. If a price is quoted per square metre of house, check the area definition and the work covered.

Keep the budget editable as decisions are made. If the windows, roof or services specification changes, update the relevant line. You can then see how much a saving on the envelope affects the total cost of the completed house.

Dividing the example subtotal before contingency by the 84 m² footprint gives about €1,322.70/m² excluding VAT. Use this figure to cross-check the calculation. It depends on every assumption above and is not a market rate.