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BUVA IsoStone Door Thresholds




BUVA IsoStone is a high strength, high quality, insulated and weatherproof door threshold, making it ideal for timber or composite doors.


Developed in the Netherlands with a 10-year track record, over half of all new doors in Holland are now fitted with BUVA IsoStone door thresholds.


The BUVA IsoStone threshold maintains its quality appearance with a high abrasion UV-resistant corundum granule surface coating for a long-wearing and durable finish. It is made from ultra-light glass reinforced plastic (GRP) and boasts impressive performance benefits including a 15mm upstand threshold for easy access. As well as this, BUVA is designed to prevent rotting and will not absorb water to make for longer lasting timber doors, and boasts impressive stability as it won’t bend, warp or move no matter how long a threshold you need.


Supplied made-to-measure and ready to fit, IsoStone threshold needs no onsite adjustment and fits securely to the door frame.


 Proven high performance

BUVA IsoStone has a ten-year track record in properties across Europe. Over 100,000 metres of IsoStone thresholds are manufactured every year and it is fitted by most housebuilders in new Dutch homes.


 High performance BUVA IsoStone door threshold with  easy fitting

·         Suitable for timber and composite doorsets


·         Supplied ready to fit - no manufacturing required


·         Thermally efficient with a U-value as low as 0.89 W/m2K


·         Designed to prevent water absorption and resist rotting


·         Dimensionally stable no matter what length you need 


·         High strength insulated GRP construction


·         Lightweight - 10x lighter than stone


·         High stability to prevent warping or twisting


·         Low threshold 15mm upstand for accessibility


 Choose BUVA IsoStone for a high-performance threshold



BUVA IsoStone offers an insulated, airtight and weatherproof threshold. Its durability, airtightness and thermal efficiency outperforms traditional timber thresholds. IsoStone also significantly reduces labour time when manufacturing timber doorsets.


BUVA IsoStone door threshold features an insulated thermal break. A polyurethane insulated outer-chamber and hollowcore inner-chamber provides a U-value as low as 0.89 W/m2K. Combined with airtight seals, this creates an energy saving threshold that prevents cold-bridging beneath the door and can be used for Passive House construction.


 Weatherproof and airtight door threshold


Timber thresholds often rot and absorb water, something the BUVA IsoStone threshold overcomes.


BUVA is designed to prevent rot making its way up the jambs, alleviating the issue to give your timber doors a much longer lifespan.


Weather protection and airtightness is enhanced using proven Deventer weather and compression seals, offering a complete solution for timber, composite and PVCu doors.


The Deventer weather seal has a high resistance against harsh winds and heavy rain. It is heat resistant up to temperatures of 200 degrees and offers excellent noise insulation. Combined with IsoStone technology, this provides a waterproof, airtight, noise insulated and fire-resistant threshold.


 Dimensionally stable

Dimensionally stable


BUVA IsoStone won’t bend, bow or move, maintaining stability no matter what length you need for your doors.


It also has a thermal coefficient of expansion of 0.4mm for a 1 metre length at 50 degrees centigrade. Its superb dimensional stability means IsoStone will not twist or warp even in extreme temperatures.


 Strong and highly secure door threshold

High Strength


IsoStone features a high strength twin-chamber glass reinforced plastic (GRP) structure that is practically unbreakable. BUVA IsoStone thresholds can be used in high security doorsets for effective intruder resistance.


 Save time and cost with the BUVA IsoStone threshold

Saves time


Installing timber doors using high quality BUVA IsoStone thresholds saves time. The threshold is supplied ready to fit to the door frame with an easy to use air and water tight fixing kit.


IsoStone threshold is ordered to exact size and made to measure from BJ Waller. With no onsite adjustment, it saves labour time and reduces the cost of the completed doorset. BUVA IsoStone threshold is fitted to the door frame upright using a proven pre-shaped polyurethane support-plinth and stainless steel fixing kit. A compression seal provides a water and air tight joint.


BUVA IsoStone threshold can cut manufacturing costs for joiners and overcomes the issue of using the more brittle timbers for the threshold, making IsoStone a high quality and cost-effective choice for timber doorsets.


The threshold is fitted to the door frame using Quick Connect fasteners, a specially designed hollow metal connector that’s simple to use and compatible with all timber applications. IsoStone is also easy to handle because its structure is ten times lighter than stone.


 Use BUVA IsoStone thresholds for timber, composite or PVCu doors

Door materials


The BUVA IsoStone threshold is suitable for timber, composite or PVCu doorsets. The polyurethane support plinth upstand is pre-shaped by CNC robots to perfectly suit the door jamb profile. On PVCu door frames, the plinth is shaped to suit the chambered frame profile.


 Low threshold and suitable for double and multi-pane doors

suitable for double doors


Available in an array of lengths, the high stability of BUVA IsoStone makes it a great choice for larger double doors. It features a low threshold with a 15mm upstand suitable for accessibility.


 Call BJ Waller on 01353 647111 to order BUVA IsoStone today


To find out more about BUVA IsoStone thresholds, get in touch with our specialist architectural ironmongery team on 01353 647111 or email


Take a look at our BUVA IsoStone door thresholds brochure here.

BUVA IsoStone Door Thresholds Brochure BJ Waller

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