Lorient LAS4001 25mm Threshold Plate is a slim, gently curved aluminium threshold plate designed to provide a firm and even sealing surface beneath single and double swing doors.
Measuring 25mm wide and 4mm high, the LAS4001 can improve the effectiveness of automatic drop seals and face-fixed door-bottom seals by giving the sealing gasket a smooth, consistent surface against which to close.
Its narrow, low-profile design is suitable for wheeled traffic and is particularly useful where a discreet threshold is required beneath the door.
The LAS4001 is installed on the floor or sill directly beneath a door.
It is commonly used to:
Automatic drop seals and other door-bottom seals work most effectively when their gasket closes against a firm, smooth and continuous surface.
Carpet, grout joints, uneven tiles, timber boards and changes between flooring materials can prevent a gasket from making consistent contact across the complete width of the doorway.
The LAS4001 creates a durable aluminium contact surface beneath the door. When the door closes, the selected drop seal or door-bottom gasket rests against the threshold plate rather than the uneven floor beneath it.
This helps create more consistent gasket contact and reduces open paths beneath the door.
No. The LAS4001 is a threshold plate and does not contain a flexible sealing gasket.
It should be combined with a suitable automatic drop seal or face-fixed door-bottom seal where containment beneath the door is required.
Lorient states that the LAS4001 can be used with practically any suitable drop or door-bottom seal.
The correct combination will depend on:
When installed with a suitable threshold seal, the LAS4001 can contribute towards:
The threshold plate does not provide these functions independently. Its purpose is to give the associated sealing gasket a firm and even surface against which to close.
The LAS4001 can form part of an acoustic door-sealing system by improving contact beneath a suitable automatic drop seal.
The gap beneath a door can be a significant sound-leakage path. Installing a smooth threshold plate can help the door-bottom gasket close this gap more consistently than it would against carpet, grout joints or uneven flooring.
However, the LAS4001 does not have a standalone acoustic rating.
Any quoted acoustic performance applies to the complete tested door assembly and specified sealing arrangement, including:
An automatic drop seal may not make reliable contact when it closes directly onto a soft or uneven floor.
Common problems include:
The LAS4001 provides a fixed aluminium surface across the doorway, helping the gasket maintain more consistent contact.
The LAS4001 is designed for use beneath single and double swing doors.
Suitable applications can include:
For exterior installations, suitable sealant should be applied where the threshold plate meets the door stops to help prevent water ingress.
Yes. Lorient identifies the LAS4001 as suitable for wheeled traffic.
Its gently curved profile rises to only 4mm, creating a smoother transition than a threshold with abrupt vertical edges.
Project-specific accessibility requirements should still be checked before installation, particularly where the doorway forms part of an accessible route or compliance-led design.
The LAS4001 and LAS4002 use a similar gently curved, low-profile design but are available in different dimensions:
The LAS4001 is the narrower and lower-profile option. It is suitable where a discreet sealing surface is required and the associated door-bottom gasket can be positioned accurately over the 25mm-wide plate.
The LAS4002 provides a wider contact surface and may be better suited where additional coverage is needed beneath the door.
Measure the doorway and clearance beneath the door before ordering.
Lorient states that the LAS4001 requires at least 6mm clearance between the door and floor for effective operation.
The threshold plate itself is 4mm high, so sufficient clearance must remain for the door to pass over the profile without scraping or preventing correct operation.
Also confirm:
The LAS4001 should be treated as one component within a complete door-sealing system. It does not independently soundproof, smoke-seal, weather-seal or fire-rate a doorway.
Lorient LAS4001 is a gently curved, low-profile aluminium threshold plate measuring 25mm wide and 4mm high. It provides a firm and even sealing surface beneath single and double swing doors.
| Product Name | Lorient LAS4001 25mm Threshold Plate |
| Manufacturer | Lorient |
| Product Reference | LAS4001 |
| Product Type | Gently curved, low-profile threshold plate |
| Width | 25mm |
| Overall Height | 4mm |
| Material | Aluminium |
| Standard Finish | Silver anodised aluminium |
| Alternative Finishes | Other colour finishes may be available subject to minimum order quantities, non-standard charges and additional lead times |
| Standard Lengths | 1m and 2.1m |
| Special Lengths | Other lengths may be available to special order |
| Door Types | Single and double swing doors |
| Installation Position | Floor or sill-mounted beneath the door |
| Minimum Door-to-Floor Clearance | 6mm |
| Compatible Seals | Practically any suitable automatic drop seal or face-fixed door-bottom seal |
| Main Function | Provides a firm and even surface against which a door-bottom gasket can seal |
| Containment Characteristics | Contributes towards smoke, weather, draught and light containment when fitted with a suitable threshold seal |
| Wheeled Traffic | Suitable for wheeled traffic |
| Fixing Methods | Screw fixing or suitable construction adhesive, depending on the substrate and project requirements |
| Supplied Fixings | Fixing screws are supplied; the current fitting guide lists stainless steel screws and plastic plugs |
| Plate Drilling | 4.5mm fixing holes drilled through the plate and countersunk so the screw heads finish flush |
| Masonry Drilling | 6mm masonry holes where the supplied plastic plugs are appropriate for the substrate |
| External Installation | Apply suitable sealant where the threshold plate meets the door stops to help prevent water ingress |
| UL Certification Reference | R27972 |
| UL Classification Shown in Fitting Guide | 5DL3 positive-pressure gasketing classification |
| Standalone Acoustic Rating | None stated — acoustic performance depends on the complete tested door and sealing arrangement |
| Standalone Smoke Rating | None stated — containment depends on the associated threshold seal and complete doorset |
| Standalone UK Fire Rating | None stated in the current Lorient product datasheet |
| Complete Seal? | No — the LAS4001 is a threshold plate and requires a suitable drop or door-bottom seal |
| Option | Width | Height | Typical Use |
|---|---|---|---|
| LAS4001 1m | 25mm | 4mm | Standard single-door openings, subject to the measured doorway width |
| LAS4001 2.1m | 25mm | 4mm | Wider openings, double doors or cutting into project-specific lengths |
| Special-Order Length | 25mm | 4mm | Non-standard doorways and project-specific requirements |
| Product | Width | Height | Profile |
|---|---|---|---|
| LAS4001 | 25mm | 4mm | Gently curved, low-profile aluminium threshold plate |
| LAS4002 | 40mm | 5mm | Gently curved, low-profile aluminium threshold plate |
The LAS4001 can be installed beneath:
Lorient states that the LAS4001 can be used with practically any suitable drop or door-bottom seal.
The selected seal must be suitable for:
Because the LAS4001 is relatively narrow, it is important to confirm that the selected gasket will land consistently on the threshold plate when the door closes.
Where a particular acoustic, smoke or fire performance is required, use the complete component arrangement stated within the relevant test evidence, assessment or doorset certification.
The current Lorient fitting guide states that the LAS4001 requires at least 6mm clearance between the door and floor for effective operation.
The threshold plate itself is 4mm high. The additional clearance allows the door to travel over the profile without rubbing or preventing correct operation.
The door must continue to:
Measure the clearance at several positions across the doorway and throughout the door’s swing path, as the floor may not be level.
A threshold plate can support acoustic sealing by giving an automatic drop seal a firm and consistent contact surface.
However, the LAS4001 does not have a standalone Rw or decibel rating.
Final sound reduction will depend on:
Do not specify or advertise the LAS4001 as independently achieving a particular acoustic rating.
The current Lorient fitting guide displays UL positive-pressure gasketing classification information for the LAS4001 and LAS4002 range.
This should not be treated as a standalone UK fire-resistance rating for the threshold plate.
Where the LAS4001 is proposed for installation beneath a fire-resisting door:
Store the LAS4001:
The narrow profile should be supported carefully during handling and cutting to avoid bending or distortion.
Take care around freshly cut edges and remove all sharp burrs before installation.
Lorient LAS4001 25mm Threshold Plate can be installed beneath single or double swing doors using suitable screw fixings or construction adhesive.
The plate should be measured and cut to suit the opening, positioned beneath the selected automatic drop or door-bottom seal and securely fixed without preventing the door from opening, closing or latching correctly.
Always follow the current Lorient fitting guide and check the requirements of the complete doorset before installation.
Inspect the door, frame and floor before cutting or fixing the threshold plate.
Check that:
Measure the door clearance at several positions across the doorway and throughout the complete swing path. The floor may rise at one side or immediately beyond the closed-door position.
Remove the LAS4001 from its packaging and measure the width of the doorway between the jambs or door stops.
Take the measurement at the exact position where the threshold plate will be installed.
If the plate must be cut around the door stops, measure each side carefully. Do not assume that the frame is square or that both stops are identical.
Transfer the doorway measurement onto the LAS4001 using a pencil or suitable marker.
Clearly mark:
Check all measurements before cutting.
Because the LAS4001 is only 25mm wide, accurate alignment beneath the sealing gasket is particularly important.
Cut the aluminium threshold plate using a suitable hand saw or power saw.
Support the narrow profile securely while cutting to prevent vibration, bending or damage to the anodised surface.
Cut slowly and accurately, particularly where the ends must be profiled around the door stops.
After cutting:
Position the LAS4001 on the door sill or floor in the required location before drilling or applying adhesive.
Check that:
Carefully open and close the door while the unsecured plate is held safely in position.
The Lorient fitting guide provides two installation methods:
Select the fixing method according to the floor construction, site conditions, doorset evidence and project specification.
Screw fixing creates a mechanical connection but requires confirmation that the floor can be drilled safely.
Adhesive fixing avoids drilling through the floor but requires a sound, clean substrate and a construction adhesive compatible with aluminium and the floor material.
Mark suitable fixing positions along the threshold plate.
Using a power drill and a 4.5mm drill bit, drill the required fixing holes through the aluminium profile.
Space the fixing holes sufficiently to hold the plate securely along its full length.
Because the LAS4001 is only 25mm wide, position the fixing holes carefully within the supported central section of the profile. Do not drill too close to the curved outer edges.
Countersink each hole so that the screw heads finish flush with the upper surface.
Raised screw heads could:
Return the threshold plate to its final position.
Using the drilled holes as a guide, mark the fixing-hole centres onto the floor.
Check the plate position and gasket alignment before removing it for drilling.
Remove the LAS4001 and drill the marked floor positions.
The Lorient fitting guide specifies a 6mm masonry drill bit where the supplied plastic plugs are suitable for the substrate.
Before drilling, confirm that:
Use alternative substrate-specific fixings where the supplied plugs are not suitable.
Remove all drilling dust and debris before inserting the plugs.
Insert the supplied plastic plugs where appropriate and place the LAS4001 back into position.
Install the supplied screws and tighten them evenly along the plate.
Check that every screw head finishes flush within its countersunk hole.
Do not overtighten the fixings, as this could distort the narrow aluminium profile or pull it unevenly against the floor.
The finished plate should be:
Where adhesive fixing is appropriate, prepare the floor and underside of the threshold plate in accordance with the adhesive manufacturer’s instructions.
The contact surfaces should normally be:
Do not bond the threshold plate onto loose carpet, unstable flooring or contaminated surfaces.
Apply a suitable construction adhesive to the underside of the LAS4001.
Use a controlled adhesive bead suitable for the narrow profile. Apply enough adhesive to secure the plate without allowing it to spread beyond the edges or onto the visible anodised surface.
Position the plate carefully and press it firmly into its final location.
Check the alignment beneath the door-bottom gasket immediately, as repositioning may become difficult once the adhesive begins to grip.
Keep the threshold plate firmly in position while the adhesive cures.
Use suitable weights or temporary restraint where permitted by the adhesive manufacturer, taking care not to bend or mark the aluminium profile.
Do not permit normal foot or wheeled traffic over the plate until the adhesive has achieved the required curing strength.
Curing time will depend on:
For exterior applications, Lorient states that sealant should be applied where the threshold plate meets the door stops to help prevent water ingress.
Use a suitable external-grade sealant compatible with:
Apply the sealant neatly without blocking any required drainage paths.
Once the threshold plate is secure, adjust the associated automatic drop seal or door-bottom seal according to its separate fitting instructions.
The gasket should contact the LAS4001 consistently across the full width of the doorway.
Check for:
Do not over-adjust the seal. Excessive compression can increase operating forces, damage the gasket and place unnecessary strain on the drop-seal mechanism.
Open and close the door several times.
Confirm that:
The installation must not impede the opening or closing of the door.
Inspect the LAS4001 periodically as part of the door’s normal maintenance programme.
Check for:
Clean the plate with a soft cloth and a suitable mild cleaning product.
Avoid abrasive pads, wire brushes and aggressive chemicals that could damage the anodised finish.
Remove dirt and debris from the sealing surface so the door-bottom gasket can continue to make consistent contact.
The LAS4001 is a supporting threshold component. It does not provide complete acoustic, smoke, weather, draught, light or fire containment by itself.
Final performance depends on:
Where the door forms part of a certified acoustic, smoke or fire-resisting assembly, install only the threshold and seal arrangement permitted by the relevant test evidence, assessment or doorset certification.
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