Oversill (2.5m) 100mm

Brand: EWI Pro
SKU: CMS-810-100
-9%
£22.42 Incl. VAT
£24.91 Incl. VAT (regular price)
Please note: This product has a slightly longer lead time. Our team wiil notify you with an estimated delivery date.

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    The Over-Sill is designed to extend the length of an existing window sill, ensuring that it overhangs the insulation. The purpose of this particular type of Verge Trim is to prevent water ingress behind the insulation, which can cause serious damage.

    Additional Information

    Google Category ID
    503739

    Frequently Asked Questions

    Render beads are profiles made from materials like PVC, stainless steel, or aluminium, used to shape, reinforce, and protect rendered surfaces. They provide clean lines, define edges, and prevent cracking in vulnerable areas such as corners, window reveals, and expansion joints.

    • In Thin Coat Systems: Render beads help reinforce the lightweight, flexible finishes typically applied over insulation boards. They ensure the render is evenly applied, prevent damage at edges, and accommodate movement.

    • In Monocouche Systems: Because monocouche render is applied thickly in a single coat, beads are vital for structural support, alignment, and crack prevention. They also contribute to the visual sharpness of edges and transitions.

    In all render systems, beads play a crucial role in both aesthetic finish and long-term durability.

    Corner beads are used to reinforce and straighten external corners, ensuring a strong and uniform edge.

    • Thin Coat: Often combined with mesh for additional strength; crucial in preventing cracking on vulnerable corners.

    • Monocouche: Offers a crisp finish and adds strength to monocouche render corners which are prone to damage due to the thickness of the product.

    Stop beads create a clean edge or end point in the render system, such as where the render meets another material.

    • Thin Coat: Used to give a professional finish where the system stops, like at wall ends or changes in façade material.

    • Monocouche: Helps to define edges and stop points, keeping a crisp finish and preventing cracking at terminations.

    Window beads (or reveal beads) are used around window and door reveals to create a neat edge and maintain movement flexibility between the render and frame.

    • Thin Coat: Often includes a mesh wing for reinforcement and a rubber gasket for sealing against the frame.

    • Monocouche: Helps manage expansion and contraction and ensures a clean, straight reveal around openings.

    Movement beads (or expansion joints) allow the render to expand and contract with temperature changes, preventing cracks.

    • Thin Coat: Installed at specific intervals (typically every 5–7m), especially on large, flat walls.

    • Monocouche: Absolutely essential; monocouche is more prone to cracking due to its thickness and lack of flexibility, so movement joints are vital.

    Arch beads are flexible beads designed to follow curves and arches in façades, providing a clean, crisp edge and reinforcing the render around curved surfaces.

    • Thin Coat: Used with flexible mesh-reinforced systems to maintain shape and avoid cracking around arches.

    • Monocouche: Helps define curved architectural features, but less commonly used due to monocouche’s thickness and tendency to crack without reinforcement.

    Bellcast beads (also known as drip beads) are installed at the base of a render system to direct water away from the wall and prevent staining.

    • Thin Coat: Essential to prevent water ingress and ensure the finish remains neat and long-lasting.

    • Monocouche: Also important in monocouche systems to prevent water from tracking back onto the substrate, which can lead to staining or degradation.

    Oversills are used to extend existing sills so they project beyond the new render and insulation thickness, preventing water from dripping behind the render.

    • Thin Coat: Critical when EWI is added, as original sills are often too short.

    • Monocouche: Used less frequently but still important when original sills don’t offer enough protection.

    Bead cutters are tools used to cut render beads cleanly and accurately, often including mitre guides for perfect corners.

    • Thin Coat: Helps installers maintain tidy joins and angles, particularly important in visible areas.

    • Monocouche: Also beneficial, though the beads may be thicker and require a robust cutter due to the render depth.

    Reviews & Ratings

    Overall rating

    4.5
    ★ ★ ★ ★ ★
    78 reviews
    5 stars
    53
    4 stars
    16
    3 stars
    6
    2 stars
    1
    1 stars
    2

    Have something to say?

    Rate Oversill (2.5m)

    Ian

    ★ ★ ★ ★ ★ 5
    18.12.2025
    Propr piece of kit. Water sorted.

    "Nabila,"

    ★ ★ ★ ★ ★ 5
    10.12.2025
    140mm fit was bang on, water run-off solved. Brill!

    Corneliu

    ★ ★ ★ ★ ★ 5
    01.12.2025
    Perfect fit! Just does job.

    PAWEL

    ★ ★ ★ ★ ★ 5
    28.09.2025
    110mm Over Sill was spot on. Solid material, fitted right, and totally stopped the water ingress. Exceeded expectations.

    Carwyn

    ★ ★ ★ ★ ★ 2
    31.08.2025
    Broke cutting gently. Poofr brittle PVC trim.

    mark

    ★ ★ ★ ★ ★ 5
    25.07.2025
    Perfect fit mate. Solid.

    Simon

    ★ ★ ★ ★ ★ 5
    10.07.2025
    Chunky over-sill. Killed the leak easy. Good bit of kit.

    David

    ★ ★ ★ ★ ★ 4
    26.06.2025
    Decent performance against water ingress, but the protective film was a proper nuisance trying to peel it off the lip.

    Jacqueline

    ★ ★ ★ ★ ★ 4
    07.05.2025
    brill product, sorted the water ingress easily. But the supplied length was just short of the mark. Cost me extra time joining it.

    Larry

    ★ ★ ★ ★ ★ 4
    19.04.2025
    Decent bang for buck kit. Keeps water out, but finish was rough and it had a minor scratch.

    Dawid

    ★ ★ ★ ★ ★ 5
    03.04.2025
    Spot-on 140mm depth was perfect for my insulation job. Fixed a long-standing damp issue straight away. Fit is proper snug, looks factory-fitted. Great stuff!

    Adam

    ★ ★ ★ ★ ★ 5
    22.03.2025
    Spot on 170mm. Exactly what we needed for the 120mm EWI. Proper kit, job done. Brill.

    Ashley

    ★ ★ ★ ★ ★ 4
    24.02.2025
    proper Job for Runoff. Never expected much from an over-sill but this thing properly chucks the water. Keeping the EWI system dry, spot on.

    Rupert

    ★ ★ ★ ★ ★ 5
    10.02.2025
    140mm fit bwng on. Proper job!

    Jordan

    ★ ★ ★ ★ ★ 5
    27.11.2024
    Dead easy install. Solved the overhang issue. Wall is bone dry, mate.

    David

    ★ ★ ★ ★ ★ 5
    21.11.2024
    110 was bang on for the overhang, fitted dead easy. Water ingress sorted now. Excellent!

    Rrahman

    ★ ★ ★ ★ ★ 5
    01.11.2024
    170mm depth was spot on for EWI. Quality uPVC clipped easily. Fixed the damp ingress problem. Top quality!

    Chris

    ★ ★ ★ ★ ★ 4
    21.10.2024
    Over-Sill is sound for the EWI. Material quality robust, works perfectly for water ingress. But that plastic joining piece feels way too flimsy.

    Charleen

    ★ ★ ★ ★ ★ 5
    25.09.2024
    great stuff!

    Emily

    ★ ★ ★ ★ ★ 5
    09.09.2024
    140mm depth spot on! Finally fixed that water runoff issue, job's a good un. Easy to fit and proper robust material.

    Jack

    ★ ★ ★ ★ ★ 4
    24.05.2024
    Dead solid, great for the EWI job. Sales bloke was mint sorting my query. Price is a bit steep for one gtrim.

    Michael

    ★ ★ ★ ★ ★ 4
    21.05.2024
    Sound gear. 170mm was dead on for the job; couldn't get that spec anywhere else easily. UPVC gauge feels a touch light, and needed a minor trim, but it functions well. Good value. Sorted.

    LUCIA

    ★ ★ ★ ★ ★ 5
    12.05.2024
    110mm depth was just the ticket for my 80mm. Heavy duty quick delivery. Sorted.

    Melanie

    ★ ★ ★ ★ ★ 4
    10.05.2024
    keeps the wall dry job done. Trim feels cheap/thin and the install diagram was truly rubbish.

    Ioan

    ★ ★ ★ ★ ★ 5
    09.05.2024
    over Sill fits 100mm insulation perfect. Rigid Aluminium at plastic price, dead easy to fit. Spot on!

    jeff

    ★ ★ ★ ★ ★ 4
    06.05.2024
    sutrdy material, stops the ingress effectively. Shame it chipped slightly during cutting.

    paul

    ★ ★ ★ ★ ★ 5
    04.05.2024
    Exact 200mm depth. Fit perfect over insulation and stopped the damp right away. Proper solid quality. Fast delivedry. Brill!

    Naeem

    ★ ★ ★ ★ ★ 3
    19.02.2024
    acceptable for the money, but requires a lot of sealant. It's an acceptable bit of kit & fixed the water issue. But the fit is loose and wobbly, seriously! Had a right faff shimming it & dumping half a tube of mastic in. For £27 the quality feels cheap & the 110mm is very limiting. Not worth that cost.

    john

    ★ ★ ★ ★ ★ 5
    16.02.2024
    110mm depth spot on for 70mm EWI. Kept the water out. Great stuff!

    Nick

    ★ ★ ★ ★ ★ 5
    31.01.2024
    Quality robust kit. Sorted out the window ingress, no problem. Perfect fit, absolute no brainer this is.

    Richard

    ★ ★ ★ ★ ★ 4
    16.01.2024
    Needed the full 200mm depth to clear the 150mm insulation layer; worked spot on for run-off. Decent solid kit. Sales staff were helpful checking stock beforehand. Marking it 4-stars 'cos I realised afterwards I could've got the same aluminium profile cheaper at the trade depot. Still, no complaints about the product itself.

    Andrea

    ★ ★ ★ ★ ★ 4
    20.10.2023
    solid piece of kit. The 200mm depth is spot on for the EWI overhang job done on water ingress. Only thing is, no fixings included is a real faff. Plus, wanted a better discount for the volume.

    Ewen

    ★ ★ ★ ★ ★ 5
    04.09.2023
    Brill piece of kit. Sorted the window reveals. Got this Over-Sill because I was worried about water tracking back behind the EWI. Finding a proper 110mm deep sill extension for the 75mm insulation board I was using was dead easy on your site —which saved a lot of faffing about. The fit was absolutely spot on. Installed against the existing window sill with zero issues only needed minimal trimming on the 2.5m run. It's solid stuff good thick plastic that feels built to last not the usual flimsy trim. Looks nice and tidy blending in with the verge trim I got as well. It’s already done its job in a proper downpour, giving me confidence in the long-term weatherproofing. Five stars from me for preventing a future damp nightmare. Worth the money, simple as that. One small point: it'd be mint if you sold these in more standard 1.8m or 2.1m lengths, just to cut down on wastage from the 2.5m profile. Cheers.

    Raymond

    ★ ★ ★ ★ ★ 5
    25.07.2023
    110mm was bang on for my EWI board... Fitted a doddle, robust bit of kit. Great value and fixed the leak!

    Steve

    ★ ★ ★ ★ ★ 5
    07.07.2023
    glad the 110mm depth was bang on. Fits the 70mm insuation perfectly. Took 5 mins to fit. Proper gear.

    Terri

    ★ ★ ★ ★ ★ 3
    27.05.2023
    Does the job, but quality is weak for cost.

    Benjamin

    ★ ★ ★ ★ ★ 5
    17.05.2023
    Sorted the tricky job!

    Peter

    ★ ★ ★ ★ ★ 5
    25.04.2023
    proper Overhang. Water Issue Sorted. 200mm depth was spot-on for the insulation. Easy fit looks very tidy and fixed the water issue, sorted. Decent bit of kit.

    Rob

    ★ ★ ★ ★ ★ 3
    26.03.2023
    This plastic is way too soft, frankly. You worry about putting any real force on it—the whole thing felt like it would split trying to fasten it to the old sill, had to drill slow. Required way more modification than it should for a Verge Trim supposed to fit EWI installs, seriously. The price is high considering its not Aluminium, feels like cheaper plastic than the stuff down at Screwfix, and some predrilled holes were completely wrong. Keeps the rain out ok though so thats why it gets 3 stars. Just disappointed with the quality for the money spent.

    David

    ★ ★ ★ ★ ★ 5
    22.03.2023
    140mm depth spot on for the EWI. Solid kit, proper job done easy.

    phillip

    ★ ★ ★ ★ ★ 5
    21.03.2023
    Water ingress sorted, dead easy to fit! Only trim that met my specs. Strong durable kit.

    daniel

    ★ ★ ★ ★ ★ 5
    07.02.2023
    110mm was dead on. No damp now. Really good value, works good.

    Jagwinder

    ★ ★ ★ ★ ★ 4
    11.01.2023
    Did the job & geat on 100mm ins. Just the fixing holes were slighty off. A quick drill fix sorted it.

    John

    ★ ★ ★ ★ ★ 3
    06.12.2022
    bit of a faff, finish inconsistent and had to bin the included screws- but it seals.

    Peter

    ★ ★ ★ ★ ★ 1
    04.12.2022
    this was a proper mare useless courier delayed the job costing me cash then it turned up bent to hell due to the naff packaging. the flimsy rubbish snapped cutting it the 170mm depth was completely insufficient sort out your drivers and this weak rubbish wasted week of labour

    Neil

    ★ ★ ★ ★ ★ 5
    18.10.2022
    110mm depth spot on for EWI. Solved the water headache instantly. Brill!

    Naomi

    ★ ★ ★ ★ ★ 5
    16.06.2022
    Cracking bit o kit matfe

    Steven

    ★ ★ ★ ★ ★ 5
    20.04.2022
    Tech lads were brilliant. Sound sill. Sorted.

    Michelle

    ★ ★ ★ ★ ★ 5
    23.12.2021
    140 depth perfect for the EWI. Brilliant kit!

    Jonathan

    ★ ★ ★ ★ ★ 4
    09.12.2021
    Perfect depth for the job (100mm insul covered nicely). It functions great at preventing water ingress, which is the main thing. Quality is robust enough, though I kinda wish the plastic was a bit thicker for the cost. Installation was fine, but you really should consider adding pre-drilled pilot holes every 500mm or so; it'd massively speed up site time. Good that the sales guys confirmed the size for me beforehand. Decent trim, slightly high price point.

    stewart

    ★ ★ ★ ★ ★ 5
    25.10.2021
    Brill! Exactly what the job required. The 140mm depth sorted the 120mm insulation overhang perfectly. Aluminium is proper kit not flimsy. Instructions were clear saved a proper headache sealing it right.

    Andrew

    ★ ★ ★ ★ ★ 5
    11.10.2021
    Brill stuff, the 140mm depth was spot-on. Finally got the overhang perfect so water is sorted, no more leaks. Solid trim. Fast delivery too, meant job finished today not next week. Proper reliable.

    David

    ★ ★ ★ ★ ★ 5
    29.07.2021
    Spot on 110mm for the 70mm EWI board. Decet bit of kit, feels proper premium. Job's a good'un!

    John

    ★ ★ ★ ★ ★ 5
    27.07.2021
    proper job. Fits right, good value.

    Ghulam

    ★ ★ ★ ★ ★ 1
    26.07.2021
    aBSOLHUTE SHAMBLES. I bought this cheap PVC 170mm over-sill hopinv to save a bit but now I'm paying for it twice. The whole point is to keep the run-off water clear but this thing is so flimsey it just lets water capillary back under and run straight down the basecoat. Its left a HORRIBLE ugkly streak line staining the render right underneath the cil and now I have to clean it off or re-patch the wall. TOTAL WASTE of my weekend AND my £35.88. Next time i will stick with the proper allyo profiles because this soft plastic won't see out the winter. Do NOT rely on this for serious external EWI water protectoin.

    Thomas

    ★ ★ ★ ★ ★ 5
    02.07.2021
    the 140mm depth was bang on for 100mm EWI Solved the water ingress issue quickly. High quality trim, definitely recommend this part.

    SALV

    ★ ★ ★ ★ ★ 5
    26.06.2021
    Decent kit. The 110mm depth fully stopped water ingress behind the 80mm EPS.

    paresh

    ★ ★ ★ ★ ★ 5
    26.04.2021
    140mm, ddead on, saved time. Good kit.

    Evo

    ★ ★ ★ ★ ★ 5
    07.02.2021
    Absolute lifesaver finding the 140mm depth! Everywhere else only had 120s which wouldnt work for my 100mm boards. Saved us a proper headache trying to make something fit. The best part is it's one solid integrated profile so there's **no faffing about with tape and separate drip edges**—you just lock it in and the reveals are watertight. Decent rigid PVC material, spot on price. Also arrived undamaged and quick delivery. Cracking piece of kit. Job sorted!

    Ricky

    ★ ★ ★ ★ ★ 5
    05.01.2021
    Finally a 140mm over-sill that doesn't cost sixty quid! Needed this specific depth for the thick insulation board. Spot on fit, saved me loads of faffing.

    Joseph

    ★ ★ ★ ★ ★ 5
    03.01.2021
    Amazing, 140mm fits insulation bang on. Sorted the constant leak. Feels solid and much better value than competitor trims. Highly recommend.

    Jeanette

    ★ ★ ★ ★ ★ 5
    16.10.2020
    Brilliant bit of kit this oversill. We needed the 140mm depth for our job (100mm insulation), and the finished measurements wers spot on. It went in a teat, honestly. It snapped straight into the existing EWI components and the consistency in the extrusion profile is miles ahead of the cheap ali trims I used on the last site. Saved me a load of faff with sealing the joint. Quality feels bombproof and it’s sealed the window perfectly, exactly what it should do. Looks chuffed to bits with the finished edge. Arrived quick and safe. Top product, spot on value.

    Michael

    ★ ★ ★ ★ ★ 5
    14.09.2020
    brill kit. Depth was bang on, sorted the water ingress right quick!

    Tadas

    ★ ★ ★ ★ ★ 5
    04.09.2020
    superb!

    Vadim

    ★ ★ ★ ★ ★ 5
    24.04.2020
    140mm depth spot on, quality proper, stops the trickle dead.

    Belinda

    ★ ★ ★ ★ ★ 5
    18.04.2020
    Perfet fit, 110mm sorted my EWI overhang. Solid Ali. Saves damp hassle.

    Kevin

    ★ ★ ★ ★ ★ 4
    25.01.2020
    Sound kit. 140mm size spot on for my EWI gap. Stopped the ingress. Lost a star cause cutting the 45 degree corners was proper fiddly, nearly ruined a length. Good delivery.

    Michael

    ★ ★ ★ ★ ★ 5
    26.12.2019
    140mm was the perfect fit for my insulation. Dead easy to install and feels much sturdier. Sorted.

    Preetham

    ★ ★ ★ ★ ★ 5
    22.12.2019
    Perfect fit, sorted!

    martin

    ★ ★ ★ ★ ★ 4
    18.11.2019
    100mm sorted. Lonh-run faff.

    John

    ★ ★ ★ ★ ★ 5
    29.10.2019
    nailed it! Best quality I've found.

    Paul

    ★ ★ ★ ★ ★ 5
    21.10.2019
    140mm Over Sill was spot on, cut easy, dead good finish. Sealed the EWI gap perfect, saved me a nightmare.

    James

    ★ ★ ★ ★ ★ 3
    03.06.2019
    Bit of a palaver but it worsk just.

    Lenny

    ★ ★ ★ ★ ★ 5
    29.05.2019
    Spot on, the 140mm is proper robust. Fixde my damp problem, dead easy to fit.

    Alex

    ★ ★ ★ ★ ★ 5
    10.03.2019
    140mm sill fit perfect. No leaks.

    Melanie

    ★ ★ ★ ★ ★ 3
    09.01.2019
    Average product. Spent too long battling this trim to justify the price over that cheaper plastic one I saw locally. It wasnt a proper robust profile, which added to the faff factor. Sorted now.

    Wayne

    ★ ★ ★ ★ ★ 4
    20.12.2018
    Keeps water out, dead solid. Proper pian needing an extra trip for screws.

    Jim

    ★ ★ ★ ★ ★ 5
    09.11.2018
    Got here fast. 110mm depth was a proper fit. Water ingress sorted no fuss!

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