We regularly get questions about a 225 mm insulated door upstand.
TRIOTHERM+ comes as a 230 mm standard profile. If a precise 225 mm height is required, the profile can be cut down with a suitable saw or an electric planer.
However, before reducing the height, it is worth looking at the complete floor build-up.
A floor that is planned to be 225 mm high on paper does not always finish at exactly 225 mm on site.
For example, 150 mm floor insulation laid over an uneven subfloor may sit a few millimetres higher than the stated insulation thickness. Additional tolerances in the screed, adhesive and final floor finish can also change the finished level.
Because of this, where a project calls for an approximately 225 mm upstand, we suggest considering the standard 230 mm TRIOTHERM+ profile before cutting it down.
Those extra few millimetres can provide useful tolerance while the full floor build-up is still unfinished.
Why a Little Extra Height Can Matter
The relationship between the finished floor level, the door threshold and the underside of the door leaf is critical.
If the threshold is set too low, the finished door may have very little clearance above the finished floor.
The door may then have to be raised towards the limit of its adjustment range. Depending on the door system, this can reduce the available compression or sealing tolerance at the threshold.
Small floor clearances can also cause practical problems during everyday use.
A small stone or other debris caught between the underside of the door leaf and the finished floor can stop 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 level and flatness of the structural subfloor;
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the actual 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, keeping the extra 5 mm can provide valuable tolerance until the finished floor level is established.
The TRIOTHERM+ profile can always be cut down when the door and floor detail genuinely require it. Increasing the height later is considerably more difficult.
Practical Recommendation
If the design shows a 225 mm insulated upstand but the finished floor has not yet been built, we usually 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.
When the finished floor level is not yet established, keeping the 230 mm TRIOTHERM+ profile gives useful tolerance and reduces the risk of the threshold ending up too low after the floor is finished.