Expamet BAT Splice Plates

Health & Safety Recommendations

Take normal site hygiene and safe working practices into account before installing Expamet BAT Splice Plates. Wear suitable cut-resistant gloves when handling the plates, as pre-galvanised steel edges and corners can be sharp. Eye protection should always be worn when cutting, drilling, removing decayed timber, hammering nails or working overhead. Safety footwear, suitable workwear and respiratory protection may also be required in situations where dust, debris, old timber fibres or masonry residue are present.

Before starting work, make sure the surrounding floor, ceiling or structural area is stable enough to work on safely. Rotten, fire-damaged or weakened timber can fail unexpectedly when disturbed, particularly around floor joist ends, wall pockets and bearing points. If there is any doubt about the load-bearing condition of the timber, the extent of decay, or the suitability of a splice plate repair, the area should be properly assessed by a competent builder, timber repair specialist or structural engineer before proceeding any further.

Installation Requirements

Expamet BAT Splice Plates must only be fitted in situations where the basic installation requirements can be met in full. The timber being repaired or joined must have a minimum thickness of 50mm, so that the plates and nails can achieve a secure fixing. The timbers being joined should have an equal cross-section, with a variation no greater than +/-2mm, as a poor size match can significantly reduce contact, alignment and load transfer through the splice.

The gap between the timber sections must not exceed 6mm. This is important because the splice plates have been designed to reinforce a close timber-to-timber connection, not to bridge a wide void or compensate for badly cut, misaligned or missing timber. All four plates from the set must be used to form the repair, and all nail holes should be fully fixed using the supplied nails. Leaving any holes empty or using only part of the set will reduce the strength and stability of the finished splice connection.

Site Preparation

Expose the timber section requiring repair or reinforcement and clear the working area properly before fitting the splice plates. Remove floorboards, ceiling finishes, insulation, debris or loose material as required to gain clear access to both sides of the repair zone. The timber should be visible enough to allow its condition, cross-section and alignment to be checked before any fixing takes place.

Any rotten, decayed, fire-damaged or unsound timber must be removed back to sound material. Do not fix Expamet BAT Splice Plates over soft, friable, crumbling or badly split timber, as the nails will not achieve a reliable hold. Where decay has occurred as a result of damp, leaks or poor ventilation, the source of moisture should be identified and corrected before the repair is closed up. Treating the structural symptom without addressing the underlying moisture cause will simply allow further decay to develop in due course.

Cut the timber sections to the required length and remove any sharp edges, splinters or loose fibres from the cut ends. The cut faces should be square enough to sit closely together, with the gap kept within the 6mm maximum. Align the timbers carefully so the sections match in depth and width, and check that they sit straight before fitting the plates. Accurate preparation at this stage is essential for a neat and reliable joist repair plate installation.

Installation Instructions

Once the timber has been prepared and aligned, position the first Expamet BAT Splice Plate over the splice area, so that it bridges the joint evenly and the pre-formed nail holes sit over sound timber. The plate should sit flat against the timber face, without rocking, twisting or bridging over any large surface irregularities. Check that the timber sections remain aligned and that the gap between them does not exceed 6mm.

Insert the supplied nails through the nail holes and drive them into the timber using a suitable hammer. Each nail should be seated firmly so the plate is held tight against the timber. All nail holes must be used, as the strength of the splice connection relies on the full fixing pattern rather than a reduced number of fixings. Work steadily and avoid bending nails or damaging the surrounding timber during installation.

Repeat the process for the remaining three plates in the set. All four Expamet BAT Splice Plates must be installed to create the intended splice connection. Each plate should be properly aligned, seated flat against the timber and fully nailed through every hole. Check the splice from all accessible sides as the work progresses, to make sure the timber has not shifted and the repair remains straight throughout.

Once all four plates are fixed, inspect the completed splice connection. Confirm that the plates are secure, the nails are fully driven, the timbers remain aligned and the joint is stable. If additional splice plate sets are required for further joist repairs or structural timber reinforcement, repeat the same method for each separate connection, making sure every splice meets the same preparation and fixing requirements.

Limitations & Good Practice

Expamet BAT Splice Plates have been designed for suitable localised timber repair and reinforcement, including rotten floor joist repairs, fire-damaged timber repairs and local structural timber damage, where enough sound timber remains to take the fixings reliably. They are not a substitute for full timber replacement in situations where decay, charring, splitting or structural weakness extends beyond the repair zone.

Do not install the plates onto timber that is still wet, actively decaying, severely cracked, undersized or unable to hold nails securely. Do not use the splice plates to bridge gaps greater than 6mm, to join timbers of noticeably different cross-section, or to reinforce timber less than 50mm thick. The plates should always be fitted as a complete four-plate set, with all fixing holes used, in order to achieve the intended repair detail.

Where joists are load-bearing, heavily damaged, close to a bearing wall, affected by long-term damp or part of a larger structural issue, competent advice should be obtained before any repair work begins. In older properties, decay at joist ends is often linked to damp masonry, blocked air bricks, defective rainwater goods, leaking plumbing or poor underfloor ventilation. These underlying issues should always be corrected as part of the overall remedial work.

Aftercare

After installation, the completed splice connection should be visually checked before the area is covered. Make sure the plates remain tight to the timber, the nails are fully seated and the repair is stable under normal handling. Any surrounding floorboards, decking or finishes should be refitted in a way that does not disturb the splice plates or introduce new moisture traps around the timber.

The repaired area should be kept dry and well ventilated. Where the original damage was caused by rot or damp, the area should be monitored periodically to confirm that moisture has not returned. If the repair is in a floor void, wall pocket or enclosed timber zone, maintaining proper ventilation and preventing water ingress are absolutely essential to the long-term success of the timber repair.

Other Information

Expamet BAT Splice Plates are manufactured from 1.2mm pre-galvanised mild steel and are supplied as a four-plate set with nails for fixing. They are available in different sizes to suit varying timber sections and repair requirements, so the selected plate size should always match the joist or timber being reinforced. The aim is to provide sufficient overlap onto sound timber on each side of the splice, so the repair can transfer load effectively.

For the best results, plan the repair before cutting any timber, confirm the joist size, check the condition of the remaining timber and make sure the full fixing pattern can be achieved. A properly installed splice plate repair can be a practical and cost-effective method for localised floor joist repair, structural timber reinforcement and remedial building work, provided the defect is suitable for this type of repair and the surrounding timber remains structurally sound.

Q) What are Expamet BAT Splice Plates and what are they designed for?

A) Expamet BAT Splice Plates are pre-galvanised mild steel timber repair plates designed for reinforcing and repairing localised damage in structural timber work, with a particular focus on rotten, decayed or fire-damaged floor joists. Manufactured from 1.2mm pre-galvanised mild steel to BS EN 10142:1991, DX51D+Z275, they provide a durable, corrosion-resistant fixing solution for suitable timber repair applications. Each set contains four splice plates and nails for secure fixing, helping to create a strong mechanical connection between sound timber sections. Available in three sizes (L61, L80 and L98), they are a practical option for joist repairs, structural timber reinforcement and remedial building work in situations where full timber replacement may not be necessary.

Q) What sizes are Expamet BAT Splice Plates available in?

A) Expamet BAT Splice Plates are available in three practical sizes to suit different timber sections and repair requirements. The L61 plates measure 61mm wide x 400mm long and are well suited to smaller timber sections or lighter repair situations where the dimensions match the joist or timber being reinforced. The L80 plates measure 80mm wide x 560mm long and provide greater coverage for larger joists or areas requiring increased bearing and connection length. The L98 plates measure 98mm wide x 560mm long, offering the widest plate option for more demanding repairs where additional coverage and support are needed. The selected plate size should always match the joist or timber being reinforced to ensure sufficient overlap onto sound timber.

Q) Where can Expamet BAT Splice Plates be used in building repair work?

A) Expamet BAT Splice Plates are commonly used in a wide range of remedial building, property restoration, floor repair and structural timber repair projects. Typical applications include rotten floor joist repairs at wall bearings or masonry pockets, localised timber decay repairs where rot or damp-related deterioration has affected part of a timber member, and fire-damaged structural timber repairs as part of properly assessed repair specifications. They are also useful for floor structure refurbishment, period property timber repairs, repairing damaged joists after local defects have been removed, structural timber reinforcement in building maintenance, and contractor or remedial specialist use. In each case, the surrounding timber must remain structurally suitable for a secure fixing and competent repair detail.

Q) When should Expamet BAT Splice Plates be used as an alternative to full joist replacement?

A) Expamet BAT Splice Plates should be considered as an alternative to full joist replacement in situations where timber damage is concentrated in a localised area while the rest of the joist remains perfectly serviceable. In many older properties, decay occurs at bearing points, wall pockets or exposed ends, leaving the central portion of the joist sound. In these cases, a correctly specified splice plate repair can reduce disruption to floors, ceilings and surrounding finishes, while saving time and labour. However, they should only be used where enough sound timber remains to take the fixings reliably, where the damage is suitable for localised reinforcement, and where any underlying causes such as damp or poor ventilation have been properly addressed.

Q) What are the main advantages of choosing Expamet BAT Splice Plates?

A) Expamet BAT Splice Plates offer a strong combination of practical advantages for localised timber repair work. The pre-galvanised mild steel construction provides strength, durability and corrosion resistance well suited to internal structural timber repair applications. They are manufactured to BS EN 10142:1991, DX51D+Z275, giving a recognised material basis for consistent performance. Each set includes four plates and nails, providing a balanced repair arrangement with all required fixings. Three available sizes allow the plate selection to be matched to the timber section and repair length. They offer a cost-effective alternative to full joist replacement, supporting localised structural timber repair while preserving as much of the existing structure as possible during restoration, maintenance or refurbishment work.

Q) What technical specifications do Expamet BAT Splice Plates meet?

A) Expamet BAT Splice Plates are manufactured from 1.2mm pre-galvanised mild steel to BS EN 10142:1991, DX51D+Z275. The pre-galvanised finish helps protect the steel against corrosion during normal service conditions, while the mild steel construction gives the plates the rigidity required for proper mechanical reinforcement. Each set is supplied as a four-plate kit complete with nails for secure fixing. The three available sizes are L61 at 61mm x 400mm, L80 at 80mm x 560mm, and L98 at 98mm x 560mm. The plates are designed for use on timber with a minimum thickness of 50mm, with joined timbers requiring an equal cross-section within +/-2mm variation, and a maximum gap between timber sections of 6mm.

Q) What installation requirements must be met when using Expamet BAT Splice Plates?

A) Expamet BAT Splice Plates must only be fitted in situations where the basic installation requirements can be met in full. The timber being repaired or joined must have a minimum thickness of 50mm, so that the plates and nails can achieve a secure fixing. The timbers being joined should have an equal cross-section, with a variation no greater than +/-2mm, as a poor size match can significantly reduce contact, alignment and load transfer through the splice. The gap between the timber sections must not exceed 6mm, as the plates are designed to reinforce close timber-to-timber connections rather than bridge wide voids. All four plates from the set must be used, with all nail holes fully fixed.

Q) How should the site be prepared before fitting Expamet BAT Splice Plates?

A) Before fitting Expamet BAT Splice Plates, expose the timber section requiring repair and clear the working area properly. Remove floorboards, ceiling finishes, insulation, debris or loose material as required to gain clear access to both sides of the repair zone. The timber should be fully visible to allow its condition, cross-section and alignment to be checked. Any rotten, decayed, fire-damaged or unsound timber must be removed back to sound material, as the nails will not achieve a reliable hold on soft, friable or crumbling timber. Where damp has caused decay, identify and correct the moisture source before closing up the repair. Cut timber sections square, remove sharp edges or splinters, and align the timbers carefully.

Q) How are Expamet BAT Splice Plates installed?

A) Once the timber has been prepared and aligned, position the first Expamet BAT Splice Plate over the splice area so it bridges the joint evenly and the pre-formed nail holes sit over sound timber. The plate should sit flat against the timber face without rocking, twisting or bridging over surface irregularities. Insert the supplied nails through the nail holes and drive them into the timber using a suitable hammer, seating each nail firmly so the plate is held tight. All nail holes must be used, as the strength of the splice relies on the full fixing pattern. Repeat the process for the remaining three plates in the set, ensuring each plate is properly aligned and fully nailed.

Q) Why must all four plates and all nail holes be used on Expamet BAT Splice Plates?

A) All four Expamet BAT Splice Plates must be used together because the repair detail has been designed to work as a complete four-plate connection, providing balanced reinforcement around the entire timber section. Fitting fewer plates would leave one or more faces unsupported, significantly reducing the strength and stability of the splice. Similarly, all nail holes must be fully fixed using the supplied nails, as the strength of the connection relies on the full fixing pattern distributing load across the timber. Leaving any holes empty or using only part of the set will compromise the repair, reducing its ability to transfer load effectively and undermining the structural reliability of the finished joist repair plate installation.

Q) Can Expamet BAT Splice Plates be used to repair fire-damaged timber?

A) Yes, Expamet BAT Splice Plates can be used to repair fire-damaged structural timber as part of a properly assessed repair specification, provided the surrounding timber remains structurally suitable. Where fire damage has affected a localised section but the remaining structural member can be retained, the splice plates can help reinstate support by reinforcing the cut-back repair zone. However, all charred, weakened or compromised timber must first be cut back to sound material, leaving enough good timber on each side of the splice to achieve a secure fixing. Where fire damage is extensive, structural weakness extends beyond the repair zone, or load-bearing capacity is in doubt, competent advice should be obtained before any splice plate repair is attempted.

Q) What underlying issues should be addressed before fitting Expamet BAT Splice Plates?

A) Before fitting Expamet BAT Splice Plates, any underlying causes of timber damage must be identified and corrected. In older properties, decay at joist ends is often linked to damp masonry, blocked air bricks, defective rainwater goods, leaking plumbing or poor underfloor ventilation. Treating the structural symptom without addressing the underlying moisture cause will simply allow further decay to develop in due course. Inspect the surrounding area for signs of damp ingress, condensation or ventilation issues, and ensure these are remedied as part of the overall repair scheme. Address blocked air bricks, repair defective gutters or downpipes, fix any plumbing leaks and improve underfloor ventilation where required, so the repair can perform reliably over the long term.

Q) Are there practical tips for getting the best results with Expamet BAT Splice Plates?

A) For the best results with Expamet BAT Splice Plates, plan the repair carefully before cutting any timber. Confirm the joist size and condition of the remaining timber, select the appropriate plate size (L61, L80 or L98) to suit the section being reinforced, and ensure sufficient overlap onto sound timber on each side of the splice. Cut timber sections square and remove sharp edges or splinters before alignment. Keep the gap between timber sections within the 6mm maximum, and align the timbers carefully so they sit straight and matched in depth and width. Use a suitable hammer to drive nails firmly without bending them, and check the splice from all accessible sides as work progresses to confirm alignment.

Q) What are the limitations of Expamet BAT Splice Plates?

A) Expamet BAT Splice Plates have several important limitations to be aware of. They are not a substitute for full timber replacement where decay, charring, splitting or structural weakness extends beyond the repair zone. Do not install them onto timber that is still wet, actively decaying, severely cracked, undersized or unable to hold nails securely. Do not use the plates to bridge gaps greater than 6mm, to join timbers of noticeably different cross-section beyond +/-2mm variation, or to reinforce timber less than 50mm thick. The plates must always be fitted as a complete four-plate set with all fixing holes used. Where joists are heavily damaged, close to a bearing wall, or part of a larger structural issue, competent advice should be obtained first.

Q) What health and safety precautions should be followed when fitting Expamet BAT Splice Plates?

A) Take normal site hygiene and safe working practices into account before installing Expamet BAT Splice Plates. Wear suitable cut-resistant gloves when handling the plates, as pre-galvanised steel edges and corners can be sharp. Eye protection should always be worn when cutting, drilling, removing decayed timber, hammering nails or working overhead. Safety footwear, suitable workwear and respiratory protection may also be required where dust, debris, old timber fibres or masonry residue are present. Before starting work, ensure the surrounding floor, ceiling or structural area is stable enough to work on safely, as rotten, fire-damaged or weakened timber can fail unexpectedly when disturbed, particularly around floor joist ends, wall pockets and bearing points.

Q) When should a structural engineer be consulted before using Expamet BAT Splice Plates?

A) A competent builder, timber repair specialist or structural engineer should be consulted before using Expamet BAT Splice Plates wherever there is any doubt about the load-bearing condition of the timber, the extent of decay or the suitability of a splice plate repair. This applies particularly where joists are load-bearing, heavily damaged, close to a bearing wall, affected by long-term damp or part of a larger structural issue. Period properties with multiple joist defects, areas where the cause of damage is unclear, and situations where damage extends beyond a localised section all warrant professional assessment. The plates are designed for suitable localised repair, not for complex structural issues that require a fuller engineered solution.

Q) What aftercare is recommended once Expamet BAT Splice Plates are installed?

A) After installation, the completed splice connection should be visually checked before the area is covered. Make sure the plates remain tight to the timber, the nails are fully seated and the repair is stable under normal handling. Surrounding floorboards, decking or finishes should be refitted in a way that does not disturb the splice plates or introduce new moisture traps around the timber. The repaired area should be kept dry and well ventilated. Where the original damage was caused by rot or damp, monitor the area periodically to confirm moisture has not returned. If the repair is in a floor void, wall pocket or enclosed timber zone, maintaining proper ventilation and preventing water ingress are essential to long-term success.

Q) What kind of timber damage are Expamet BAT Splice Plates not suitable for?

A) Expamet BAT Splice Plates are not suitable for timber damage that extends beyond a localised area where sound timber remains for fixing. They should not be used on timber that is still wet, actively decaying, severely cracked, undersized or unable to hold nails securely, as the nails will not achieve a reliable hold. They are not designed to bridge gaps greater than 6mm, to join timbers of noticeably different cross-section, or to reinforce timber less than 50mm thick. They are not a substitute for full timber replacement where decay, charring, splitting or structural weakness extends beyond the repair zone. Where damage is widespread, structurally significant or linked to ongoing damp issues, alternative repair methods or professional assessment are required.

Q) How does the pre-galvanised finish on Expamet BAT Splice Plates help in service?

A) The pre-galvanised finish on Expamet BAT Splice Plates helps protect the mild steel against corrosion during normal service conditions, supporting the longevity of the repair. Pre-galvanised steel is coated with a layer of zinc before the plates are formed, providing a uniform protective layer that resists moisture, oxidation and general corrosion typical of internal building environments. This is particularly important in timber repair applications where the plates may be installed in floor voids, wall pockets or other enclosed spaces where some residual moisture may be present. The DX51D+Z275 specification under BS EN 10142:1991 confirms a recognised material standard, ensuring consistent quality and reliable corrosion resistance for suitable remedial timber reinforcement work over time.

Q) Can Expamet BAT Splice Plates be used in period properties and older buildings?

A) Yes, Expamet BAT Splice Plates are particularly useful in period properties and older buildings where full joist replacement would be disruptive or undesirable. In many older homes, original timber floors and structural members are difficult or impractical to remove entirely, especially where they are tied into ornate ceilings, lath and plaster finishes or other heritage features. In these situations, splice plates allow localised repair of damaged sections while retaining as much of the original timber as possible, supporting conservation-focused refurbishment work. However, the repair detail must still be appropriate, the surrounding timber must remain structurally sound, and any underlying causes such as damp masonry, blocked air bricks or poor ventilation must be corrected as part of the overall remedial work.

Technical Data Sheet - L61 BAT Splice Plates

Technical Data Sheet - L80 BAT Splice Plates

Technical Data Sheet - L98 BAT Splice Plates

Technical Drawing 1

Technical Drawing 2