We regularly receive enquiries for a 225 mm high insulated door upstand.
TRIOTHERM+ is available as a standard 230 mm profile, and where an exact 225 mm height is required, the profile can easily be reduced using a suitable saw or an electric planer.
However, before reducing the height, it is worth considering the actual finished floor build-up.
A floor construction that is designed as 225 mm high on paper does not necessarily finish at exactly 225 mm on site.
For example, 150 mm floor insulation installed over a relatively rough or uneven subfloor may sit a few millimetres higher than the nominal insulation thickness suggests. Additional tolerances within screed, adhesive and the final floor finish can further affect the final level.
For this reason, where a project calls for an approximately 225 mm upstand, we would generally recommend considering the standard 230 mm TRIOTHERM+ profile before reducing its height.
Those additional few millimetres can provide useful tolerance while the complete floor build-up is still unfinished.
Why a Little Extra Height Can Matter
The final relationship between the finished floor level, the door threshold and the underside of the door leaf is critical.
If the threshold is installed too low, the completed door may end up with very little clearance above the finished floor.
The door may then need to be adjusted upwards close to the limit of its adjustment range. Depending on the door system, this can reduce the available compression or sealing tolerance at the threshold.
Very small floor clearances can also cause practical problems during everyday use.
A small stone or piece of debris trapped between the underside of the door leaf and the finished floor can prevent the door from moving freely and, in the worst case, scratch or damage the floor finish.
Allow for Construction Tolerances
The specified floor build-up should therefore be treated as a nominal design dimension rather than an absolute finished-site dimension.
Before reducing a 230 mm TRIOTHERM+ profile to 225 mm, consider:
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the actual level and flatness of the structural subfloor;
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the real installed thickness of the floor insulation;
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screed tolerances;
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adhesive and floor-finishing thickness;
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the required threshold position;
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the adjustment range of the selected door system.
Where there is uncertainty, retaining the additional 5 mm can often provide valuable tolerance until the finished floor level is established.
The TRIOTHERM+ profile can always be reduced where the door and floor detail genuinely require it. Increasing the height later is considerably more difficult.
Practical Recommendation
If the design indicates a 225 mm structural insulated upstand but the finished floor has not yet been constructed, we generally recommend checking whether the standard 230 mm TRIOTHERM+ profile can be retained.
Those 5 mm may seem insignificant during the design stage, but they can provide useful installation tolerance and help avoid problems once the door and final floor finish are in place.
Where the finished floor level has not yet been established, retaining the standard 230 mm TRIOTHERM+ profile can provide useful tolerance and reduce the risk of the threshold ending up too low once the floor is completed.