A Timber House Mortgage Question Is Usually a Paperwork Question

When a surveyor or a lender comes back with a query about a solid timber house, the query is seldom about wood. It is usually a request for a document nobody thought to send: a product assessment, a calculation, a test report. Behind a timber house mortgage question there is often one missing paper, and buyers tend to find that out late, with the valuation already booked.

So it pays to know which documents exist, what each one covers and where it stops, before anyone asks. One limit first: we do not lend money or write insurance policies. Nothing here is advice on either, and no document can tell you in advance how a particular bank or insurer will decide.

Three readers looking at the same house

A surveyor, a bank and an insurer look at a timber house for different reasons. All three want the same proof, though: that the house on paper is the house being built. Their questions overlap far more than buyers expect.

The surveyor has to identify the construction and confirm it matches a sound, documented design. With brick and block, years of seeing the same walls fill a lot of gaps. A surveyor who has met few cross-laminated or dowelled solid walls has less to go on by eye, and leans on paper instead.

The bank wants to know the property is durable security. It relies heavily on the surveyor's report, and on evidence that the build meets local requirements. The insurer is blunter. It wants to know what the walls are made of. Then how they behave in a fire. Then what a rebuild would involve. Each of those has a document that answers it, and none of them is answered by a brochure.

The papers that answer a timber house mortgage question

Four kinds of document do the work here. Each covers one defined thing, never the whole house, and the trouble starts when someone treats one of them as if it covered more.

CE marking describes the product, not the house

CE marking shows that a construction product was assessed against a stated European specification. In the EU it applies to construction products covered by a harmonised European standard or by a European Technical Assessment under the Construction Products Regulation, and it comes with a declaration of performance that lists the declared values. Glulam, for example, is produced to EN 14080.

These papers describe the product as supplied. They do not approve a house, a foundation or a design in any country, and a careful surveyor will read them exactly that way. What they do let a reader confirm is that the panel or beam on site is the one the declaration describes. That is narrower than many buyers assume, and still useful.

Calculations made for your plot, not one like it

Structural calculations show that the specified panels, beams and connections carry the loads of this building on this site. Snow and wind depend on where the plot is. Spans, openings and bracing depend on the plan. The connection to the foundation depends on both. In much of Europe, timber structures are designed to Eurocode 5 with the relevant national annex, while local building rules decide what the authority needs to see.

Ask for calculations that carry the project address and the drawing revision they were made for. A general span table or a typical design describes a house like yours. That is a weaker thing to hand a surveyor than a calculation for yours, and an experienced one will notice.

Fire and airtightness reports come with conditions

A fire resistance report gives a classification for one tested construction, at a stated thickness and under a stated load. Loadbearing walls are tested to EN 1365-1. Before anyone relies on the report, the wall on your drawings has to match the wall that was tested, and the conditions printed in a fire test report are where that match is made or lost.

An airtightness test measures how much air leaks through the finished envelope at a set pressure difference. It tells you about envelope quality and feeds the energy calculation. It says nothing about structure or fire, and cannot stand in for either.

Whether the test is required is a national matter. In England, the 2021 edition of Approved Document L, in force since June 2022, requires new dwellings to be pressure tested; other countries set their own rules, and a buyer should confirm them locally. The test can only be done once the envelope is closed, so its result arrives with the completion paperwork rather than with the mortgage application.

Build the file before anyone asks

These documents do their job when they sit together in one file that matches the house as specified, ready before the surveyor visits. The delays worth watching for come from mismatches inside that file:

• a fire report for a thicker wall than the one drawn;
• calculations made on an earlier drawing revision;
• a declaration of performance for a related product, not the one ordered.

Who supplies each paper depends on the contract. In a kit purchase the manufacturer may provide the product documents and often the structural design of the shell, while the foundation, services and airtightness test can sit with other parties. Check which papers follow which scope of delivery before you sign. A gap in scope turns into a gap in the file.

Here is how it tends to go wrong. A family planning a year-round home chooses its wall build-up, moves some windows late in design, and only later finds that the structural calculation still shows the old openings. Nothing is wrong with the house. The paper describes an earlier version of it, and somebody now has to reissue it while the valuation waits.

If you are comparing suppliers of a solid timber house, ask early which of these documents come with the package and which you will have to commission yourself. A slow, complete answer at that stage is worth more than a quick one after the valuation is booked.

When the file does arrive, open each document beside your drawings. Find the product or wall build-up it names and compare it with yours. Check the thickness it states. Then look for the project address and drawing revision, and if it refers to an earlier one, ask for it to be reissued before the surveyor sees it.