Timber homes in the Canaries: winter and summer joints and SLC alternatives

Why timber changes size: sun, moisture and drying

Wood exchanges moisture with the air and can change dimensions as it dries or takes up moisture. Understanding its behaviour means considering moisture content and exposure. Exterior surfaces also need protection against sunlight and water, along with maintenance of the finish.

To understand a particular case, consider the type of timber, age, orientation, coating and maintenance history. Solid timber, glued laminated timber and a timber frame wall are different construction solutions and should be assessed accordingly.

Winter and summer: photographs of timber joints and cracks

Four photographs of the same structure, described by their contributor as glued laminated timber. The winter/summer labels follow their account, not the file dates. The location has not been verified: these images illustrate this case and are not presented as photographs taken in the Canaries.

Winter · Close-up of cracks

Summer · Wall junction

Summer · End grain and side faces

Summer · Profile and joint detail

Glulam in winter and summer: why joints can open

Glued laminated timber still exchanges moisture with its surroundings. It can shrink in drier conditions and swell as it takes up moisture. Sun, orientation, rain and ventilation matter more than the season's name. Not every facade in Tenerife behaves alike.

For the photographed case, the owner identifies a winter view with a closer fit and the other views as summer photographs showing gaps. These are case observations, not a scaled test or moisture measurements. A tighter winter joint does not establish that the detail works throughout the year.

A crack within a member is different from a gap between members

The photographs show both end-grain checks and separation at junctions. A check alone does not establish structural failure: its significance depends on depth, location and the member involved. A photograph alone cannot establish adhesive delamination either.

An open joint calls for checking the continuity of the water and air protection. If it crosses the envelope or interrupts its sealing layers, it may allow leaks or draughts. The apparent gap size in a photograph is insufficient to assess its extent; the complete junction needs inspection.

Building timber homes in the Canaries: every detail matters

Choosing good timber is one part of the project. Drying, storage before assembly and details that accommodate dimensional changes also matter. An exterior finish cannot replace a properly designed junction.

Assembly that does not accommodate movement can leave open joints, poorly sealed junctions and routes for water ingress. Timber installed too wet, unsuitable fixings and inadequate flashings are factors to check. The photographs illustrate what needs attention; attributing every defect to workmanship requires inspection.

Look for a team with demonstrable experience in your chosen system. Ask to see completed work, construction details and a maintenance plan. Experience in another building method does not by itself demonstrate expertise in timber housing.

Protecting exterior timber: a coating cannot do everything

Exposed glulam needs protection from water and sun, particularly at end grain and junctions. Eaves, drips and flashings should shed water; the finish must suit the exposure and be maintained. Filling a crack without addressing water ingress does not remove its cause.

Keeping timber exposed makes upkeep part of the cost of the home. Where reducing structural exposure is the priority, consider a wall assembly that protects the frame with exterior layers designed for that purpose.

Why consider a frame protected by the building envelope

In a framed wall, the structure can sit behind cladding and layers controlling water, air and vapour. Weather protection can then be designed without relying on every exposed timber joint also being the weather seal.

Enclosing timber does not mean simply wrapping it in an impermeable layer. The assembly must drain any water that enters and allow drying, with ventilation and vapour control designed for the project. A poorly detailed frame can also trap moisture. The benefit we seek is a protected structure and a maintainable envelope.

Building near the sea: salt air, moisture and corrosion

A coastal plot calls for an assessment of exposure to the marine environment. Salinity and moisture matter for corrosion of metal components, including screws, fittings, anchors and profiles. Timber homes also contain these components.

When comparing timber with steel and cellular concrete, review connection protection and details that keep water out. A steel structure's protection must suit its exposure; galvanising does not make every design suitable for every seaside location.

A home beside woodland: materials and wildfire risk

For a plot close to woodland vegetation, fire protection needs to inform the project from the start. The Canary Islands government's guidance for isolated homes addresses roofs and facades, clearing plant debris and protecting the area around the home.

Ask the technical team to assess the plot and the complete building: structure, walls, roof and protective details. Choosing steel with cellular concrete does not by itself make a home immune to wildfire. Performance must be established for the complete design.

Compare equivalent performance

Why we recommend SLC for a home in the Canary Islands

For a permanent home, we recommend SLC for its stable galvanised steel frame, which does not shrink as timber dries, does not rot and is not a food source for termites. With a well-designed envelope, it can also reduce the care required by timber cladding exposed to sun and rain.

Galvanised steel also needs appropriate protection details and moisture control. Steel Construction Institute guidance emphasises preventing water ingress and condensation. The specification must suit the home's exposure; the word 'galvanised' does not replace project design.

We design for safety and durability through structural calculations, fire and corrosion protection, and the details of the complete envelope. Performance, warranties and planned maintenance are set out in the design and proposal.

General viewWall layers

SLC walls can have different build-ups. Insulation, boards and finishes are selected together for the location and the project.

Is paying more for SLC worthwhile?

In our proposals, SLC usually costs slightly more than a comparable timber solution. We recommend considering that investment for structural stability and less upkeep of exposed timber. We show the difference on the same scope: floor area, foundations, transport, assembly, services and finishes.