Buying an insulated house. How to find out what is behind the finishes

Choose a room with a distinctive feature such as a dormer or a recess under the stairs. It will help you identify the correct construction photograph.

Enter the current room name and the one used by the previous owner on the plan. A former laundry might now be a study. The name change often explains an apparent mismatch between photographs and job notes.

Read the variant, thickness and date on the invoice. Look for a pack label from the same delivery or a contractor’s note connecting it to a location. List each thickness separately if several were supplied.

Check whether some of the order was returned or used on an extension. If the invoice covers the whole house but the work record mentions only the upper floor, seek further information before assigning boards to the ground floor.

Arrange the records by work date. A later roof covering replacement may have changed the layers on one roof section. Give that section its own entry.

For a note mentioning a leak repair, ask which area and layers were repaired and whether completion photographs exist. Keep both dates so a future contractor can distinguish the original installation from the repair.

If the owner provides access to an existing hatch, describe the visible layer and its position precisely. An exposed edge records one point. How far that finding extends depends on the other records.

Record identifiable features such as a metal facing or a visible product marking. Where the interior finish conceals the board, leave its exact properties open until documents or an agreed inspection establish them.

For each element, retain the source, location and open question in separate fields. For the roof above the kitchen, for example, the source might be a post-renovation drawing while the thickness of a second layer still needs confirmation.

Prioritise questions according to the planned work. If roof windows are to be replaced first, you need their junction details sooner than information about the utility room floor.

Name document copies by room, element and year. Keep original photographs alongside the annotated plan. A wide view showing where a close-up was taken helps someone visiting the house for the first time.

After your first alteration, add what the contractor found on opening the lining and what was actually installed. You can then replace an earlier assumption with a photograph, measurement and date.