Blog/Timber construction: CLT, frame and post-and-beam
Contractors

July 13, 2026

5 min read

Timber construction: CLT, frame, post-and-beam (2026 guide to choosing right)

On site, the choice of construction system changes everything. Installation time, load-transfer constraints, routing for services, level of prefabrication — you need a solution that's reliable and easy to explain to the client. Here's a concrete rundown to help you decide fast and lock down your measurements.

Contents

Understanding the three main timber construction systems

CLT: solid panels for walls and floors

CLT (cross-laminated timber) assembles cross-oriented layers of panels. The result is very rigid elements that serve as walls, floors or roofs. It's often prefabricated, with openings cut in the workshop, to save time on site and limit rework.

Timber frame: studs, bracing and insulation infill

Timber frame construction relies on closely spaced studs, with a bracing panel (often timber-based) for stability. Insulation is placed between the studs. Airtightness and water protection are then managed with membranes and suitable cladding. It's the most common solution for single-family homes.

Post-and-beam: long spans and layout freedom

Here, the structure is carried by posts and beams in solid or glue-laminated timber. This gives long spans and open spaces. The façades become infill, which makes large glazed openings and future layout changes easier.

Choosing the right timber solution for the job site and use

Single-family homes: speed, budget and thermal performance

For a house, timber frame and prefabricated walls bring a time saving, with less exposure to weather delays. On budget, standardised modules and careful insulation limit rework. Keep thermal bridges and airtightness in mind to hold performance. If you need to manage comfort despite the lightness of the frame, also see how to compensate for the lack of thermal mass.

Loft conversions and extensions: weight, site access, phasing

For a loft conversion, timber is an ally for reduced weight. It loads the foundations less, and prefabrication simplifies access when crane use is difficult. Prepare a clear phasing, getting watertight and airtight quickly, then finishes on an occupied site.

Small multi-unit and commercial buildings: span, acoustic performance, fire safety

For small multi-unit and commercial buildings, the choice is driven by spans (glue-laminated beams, CLT floors) and the acoustic target. Plan suitable floor assemblies and linings, without going "all timber" everywhere. Fire safety is addressed from the design stage, with protections and junction details.

Technical watch points: what makes timber construction succeed

Airtightness and moisture management: avoiding defects

In both retrofit and new build, the performance of a timber wall depends on perfect continuity of airtightness. Treat junctions, penetrations and window connections. On moisture, choose a suitable vapour barrier (often smart/variable-permeability) and avoid condensation traps in the insulation.

Acoustics, vibration and fixings: plan from the design stage

Timber is lightweight. Without precautions, impact noise and vibration travel easily. Plan decoupled systems (resilient strips, suitable hangers) and a "mass-spring-mass" logic. Fixings must be properly sized and compatible with the substrate to limit creaking and deflection.

Protecting timber: moisture, insects, bearing details and cladding

Protect the timber from the start of the job. Dry storage, flashing details, drip edges, ground clearance. On façades, respect the ventilated air gap behind cladding and the bearing points to avoid rising damp. In at-risk areas, plan for insect protection and local requirements.

Regulations and installation in 2026: what you need to check

British Standards, Eurocode 5 and product marking: the essentials to check

In 2026, base your installation on the applicable British Standards and the Eurocode 5 design rules for timber structures (BS EN 1995 and its UK National Annex). On products, check UKCA or CE marking where it applies, along with the Declaration of Performance, installation guides, and batch traceability.

Fire and acoustic requirements: documents and proof to provide

To secure handover and funding eligibility, keep clear evidence, especially for timber.

  • Fire. Fire test reports or classification (reaction and resistance), validated systems, and manufacturer documents consistent with the work as installed.
  • Acoustics. Technical data sheets, decoupling details, and, where required, measurement results or certificates depending on the building.

Whole-life carbon: impact and choice of timber materials

There is no whole-life carbon requirement in the Building Regulations yet, but clients and planning authorities increasingly ask for a whole-life carbon assessment to the RICS methodology, backed by EPDs to BS EN 15804. Timber can help on the embodied carbon side if you choose references with up-to-date data and limit oversizing and unnecessary treatments.

Site organisation and profitability: saving time with timber

Workshop prefabrication and logistics: deliveries, lifting, storage

In the workshop, you build timber walls and floors under cover. On site, it's mainly assembly, so fewer hours and less exposure to weather. On logistics, time deliveries carefully, plan a lifting scheme, and provide a ventilated storage area protected from rain.

Coordinating trades: technical work packages, cladding, airtightness

The time saving is decided at the interfaces. Reservations, reinforcements, service runs, all must be validated before fabrication. Installing membranes, then cladding, must maintain continuity of airtightness. A coordination meeting and checks during installation limit rework.

Quotes and margins: sensitive line items, options, what to price

To protect your margin, isolate the line items that tend to run over. Transport and crane hire, moisture protection, hardware, sealing, and workshop preparation time. Add clear options on finish levels and critical details. The ancillary trades are priced in the same work plan, with a library of work items and free lines. To frame your pricing and avoid omissions, also check the mandatory information required on a quote.

Key figures

20–30 cm

Frame wall thickness

10–15%

Timber share of new builds

0.12–0.15 W/m·K

λ timber

Frequently asked questions

In new homes, the air-permeability test is required under Approved Document L and is done at the end of the job, after windows are fitted and membranes treated, following the ATTMA measurement procedure. Plan a pre-test before interior cladding to fix leaks at junctions (windows, penetrations, floor/wall connections). Document the critical points with photos and product data sheets to secure handover.

Share this article

Pierre-Louis Guhur

Pierre-Louis is CEO and co-founder of Argile. He holds a PhD in machine learning, written at Inria, and renovated a house with his own hands in 2017 before founding the company. On the blog he writes about what he implements in the software: the 3CL-DPE 2021 method, NF EN 12831 and building physics as a calculation engine has to handle them, assumption by assumption.

Further reading

With argile

The quoting software for the electrician, the plumber and the plasterer

Electrics, plumbing, plastering, joinery, painting: every trade has its own library of work items with its units and your prices, and every line lands in the same quote as the heat pump or the insulation, without switching software.

ContractorsJune 29, 2026
Timber-frame house: compensating for the lack of thermal mass

In a timber-frame house, everything happens fast. Solar gains climb sharply, then the temperature drops as soon as the sky clouds over or night falls. As a tradesperson, you can smooth out these swings with simple choices in design, materials, and settings, without adding weight to the job.

5 min read

ContractorsApril 16, 2026
Roof frame survey: the termite check before insulating

A roof frame survey before insulation is not an inspection by eye, it is a regulated document. In France the statement on the presence of termites is required when selling a building located in a zone designated by prefectoral order, it lists the parts inspected and those that could not be, and it is valid for six months. Outside that case nothing compels you to produce it on an insulation job, but closing up timber without it means taking on its condition.

5 min read

Reveal your expertise

One demo, and you see your expertise proven.

Contact us