Dalsan BoardeX vs standard gypsum: exterior sheathing

Leaving exterior sheathing exposed to autumn rain is either a planned construction phase or an expensive teardown. The difference is the board surface and the core.

On ventilated facades, contractors sometimes try to save money on the sheathing by using standard paper-faced plasterboard, assuming the insulation and cladding will hide the substrate. The reality often arrives on the scaffolding, when the programme slips and the boards sit in the rain.

1. The paper-facing problem

Standard plasterboard relies on a cellulose paper facing. If installation slips and the boards stay wet:

• the paper can delaminate from the core;
• mould can colonise the damp paper inside the ventilated cavity;
• the board loses its strength long before the facade is finished.

Dalsan BoardeX removes that weak point. Its face is an orange glass-fibre mat, not paper, and its core is mould-resistant (ASTM D3273 score 10). It is classed A1 non-combustible (DoP-AL-013), and it is supplied in 12.5 mm and 15 mm thickness, 1200 × 2400 mm.

2. Fixings and wet cavities

In a wet ventilated cavity, humidity stays high for long periods. Fixings that are not designed for it corrode, and the board can lose its grip on the frame under wind suction. Choose fixings and a fixing pattern that match the board manufacturer's installation instructions, and check them against the project's wind load.

3. Open-weather exposure

Any exterior board has a limit on how long it can stay uncovered, and that limit must come from the producer's documents, not from a blog post. Ask us for the current BoardeX datasheet and DoP, and read the permitted exposure period and the fixing instructions before you plan the programme.

4. Sourcing through EuConX

Western European glass-mat sheathing often carries a large brand premium. Through our 4PL sourcing model, EuConX connects developers and contractors directly to Dalsan's production in Turkey. Pallets arrive with the DoP of the supplying plant, and customs, ATR and delivery are coordinated in one file. See the CE marking guide for what to check on arrival.

Have an upcoming facade project? Contact our team or see our partners.