OVER SILL WHITE 2.5m 170mm DEPTH

The 170 mm is the third of four projections in the white oversill line, sitting between the 140 mm and the 220 mm on a shared 2.5 m length. It belongs to the white and anthracite oversill and verge trim collection at Renders World, alongside the matched end caps and the anthracite profiles at the same four depths.

What the Over Sill White 2.5m 170mm Depth Does on a Rendered Wall

The Over sill white 2.5m 170mm depth is listed by Renders World at £27.90 for a 2.5 m length, August 2026, and carries the drip edge of a window sill outward once insulation and render have closed over the original one. Its function is water management: rain leaves the opening at the front edge instead of tracking back down the new render face.

Depth is therefore the entire decision on this product, and it is the one dimension the listing fixes exactly at 170 mm. How far that projection needs to reach past the finished wall is a project figure, taken from the measured build-up and the system supplier's sill detail, so the comparison further down ranks the four depths on price and step size rather than assigning each one an insulation band.

• Third step of four, £4.00 above the 140 mm: the usual move up when a 140 mm projection looks marginal against the build actually measured on the wall.
• £2.50 below the deepest profile: the gap to the 220 mm is the narrowest in the range, so where the build is genuinely deep there is little saved by stopping here.
• One 2.5 m length per opening: most domestic openings take a single length, which keeps the trim line free of an intermediate joint to seal and to see.
• Stock-tracked in the store record: unlike the 140 mm, this depth carries inventory management, so the counter can confirm quantity before a multi-window order.
• Matched white end caps listed at £5.90: the white sill and verge end cap pair is a stocked line, August 2026, not a special order.

White Oversill Specification: What Was Sourced and What Was Not

This audit publishes only what was read live this session. The previous version of this page asserted a material, an insulation band, a drip projection, a fall angle, fixing centres and a service life, none of which had a retrievable source; each is now either removed or replaced by the route to a firm answer.

Property	Position, August 2026
Listed title	OVER SILL WHITE 2.5m 170mm DEPTH
Colour	White
Projection, from the product name	170 mm
Length, from the product name	2.5 m
Price	£27.90 per profile, product record, August 2026; no VAT treatment displayed with the figure
Availability	Available and stock-tracked in the store record
Material, coating and gauge	Not published — no manufacturer sheet was retrievable this session
Insulation build accommodated	Not published — a manufacturer and project figure, not a house figure
Drip projection past the render face	Not published — comes from the system supplier's sill detail
Fall angle and fixing centres	Not published — taken from that same detail for the build-up in use
End caps	Separate item, white pair, £5.90, August 2026
Delivery	Site-wide policy: courier, pallet or company van, kerbside, carriage confirmed after the order

 

Two Renders World pages have given this depth different insulation bands — 100–140 mm here, 90–120 mm in the 140 mm page's comparison table — and no supplier document was reachable to settle which is right, so neither is republished. The practical instruction is short: measure adhesive, board, basecoat and finish on the wall, then send that figure and the elevation's exposure to the technical desk, which produces a defensible depth in one call.

How to Install the 170 mm Oversill Within the Render Sequence

Fitting an oversill is a sequencing job before it is a fixing job, and this order keeps the water path continuous and the visible face clean.

1. Confirm the depth against the wall, since measured board and render thickness on site can differ from what the drawing specified.
2. Set an outward fall before fixing, so water runs off the front edge rather than standing on the profile or working back toward the substrate.
3. Bed the rear upstand in a continuous low-modulus silicone line against the original sill — one uninterrupted bead, not spots, is the watertight detail.
4. Fix mechanically along the upstand at the centres the system detail gives for the build-up in use.
5. Leave 2–3 mm clearance at each cut end so the cap seats without being forced, and deburr the cut edge before sealing.
6. Close both ends with the white cap pair and tool the joint, finishing and sealing each cut end in one action.
7. Where the profile arrives with a protective film, leave it on through basecoat and topcoat and peel it once the render has cured; cementitious splash is far easier to prevent than to lift off a pale finish.

Measuring every opening individually is worth the extra few minutes on older solid-wall properties, where reveals on one elevation are rarely identical and a single measurement carried across four windows shows up as an uneven trim line. The oversill is one junction in a wider reveal treatment, with jamb terminations handled by stop bead profiles and external arris points by corner bead profiles. For the order of work in full, the window sill extension fitting guide covers measuring and cap closure, and the guide to render detailing at windows and doors covers how the profiles around an opening coordinate.

Choosing Between the Four White Depths and What the Step Costs

All four share the 2.5 m length, the white finish and the same end cap pair, so depth and price are the only variables. Every figure was read from the product records in August 2026, is material cost only, and carried no displayed VAT treatment.

Profile	Depth	Price, Aug 2026	Step from this depth
110 mm white oversill	110 mm — shallowest	£20.90	−£7.00
140 mm white oversill	140 mm	£23.90	−£4.00
Over sill white 2.5m 170mm depth (this profile)	170 mm	£27.90	—
220 mm white oversill	220 mm — deepest	£30.40	+£2.50

 

The full spread is £30.40 − £20.90 = £9.50 across 110 mm of projection, so depth is a small line on a materials budget and specifying short to save money rarely pays. On this profile the rate is £27.90 ÷ 2.5 m = £11.16 per linear metre, the figure to carry into a take-off across several openings. Worth noting where the money actually sits: the step up from 140 mm to 170 mm costs £4.00, while the further step to 220 mm costs only £2.50, so a build-up sitting near the top of this profile's reach is often better served by the deeper trim.

Working Out Quantities, Caps and Carriage Before Ordering

Oversills are counted by continuous runs rather than by windows, and the caps are the item most often left off an order sheet.

• One profile plus one cap pair per run: £27.90 + £5.90 = £33.80 in materials for a single opening, before sealant and fixings.
• Count caps by runs, not by openings: a bay made from three sections takes three pairs; one window closed by one length takes one.
• Cap price is independent of depth: the same £5.90 pair closes a 140 mm or a 220 mm run, so a mixed-depth elevation still costs one pair per run.
• Match cap colour to the run at order stage, white with white and anthracite with anthracite, rather than painting a cap afterwards.
• Confirm cap seating on this depth with the desk, since no manufacturer document for the pairing was retrievable this session.
• Carriage is quoted, not calculated: the Renders World shipping policy covers courier despatch for small parcels up to 25 kg next day, pallet service up to 1200 kg, and local company van delivery, all kerbside, with the method confirmed by customer service after the order because the store cannot price carriage automatically across products of this size range.

Collection from Southampton is one route among those rather than the only one, so a 2.5 m profile can be planned into a delivery with the rest of a system order — including the reinforced layer and the thin-coat silicone render that finish over the trim.

Is the 170 mm White Oversill the Right Depth for Your Elevation?

• Where the build-up needs more clearance than 140 mm gives: a sound choice on a white trim scheme when the measured finished face sits comfortably inside 170 mm of projection.
• Where the projection is still marginal: the 220 mm white oversill is £2.50 more, the cheapest step in the range and the sensible move when the figures are close.
• Where the build is modest: the 140 mm white oversill keeps the trim proportionate to the wall and saves £4.00 per opening.
• Mixed elevations on one property: depths can be mixed across a facade while the cap, the colour and the length stay constant, so label profiles by elevation on the order sheet and keep the cuts off the wrong wall.
• Dark or contrast trim schemes: the anthracite profiles at all four depths sit in the same oversill and verge trim collection.

FAQ — Depth Choice, Quantities and Ordering the White Oversill

How do I know 170 mm is deep enough?

Add up the full build you are applying — adhesive, board, basecoat and finish — then check the 170 mm projection clears that figure by the drip margin your system detail asks for. Both the required margin and the insulation band are manufacturer figures this page could not source, and two Renders World pages currently quote different bands for this depth, so the reliable route is to send the measured build-up and the elevation's exposure to the technical desk before ordering.

How many profiles and cap pairs does one window take?

One 2.5 m length covers most domestic openings without a joint, and one cap pair closes that run at both ends.

• Single opening, one length: one profile and one pair, £33.80 in materials.
• Bay in three sections: three profiles as measured and three pairs.
• Opening wider than one length: plan the joint away from the visual centre of the window.

Is it worth paying £4.00 more than the 140 mm?

That depends on measured build depth rather than preference, and the arithmetic is short: £23.90 against £27.90 across a handful of openings is a few pounds, while a projection that turns out too shallow is a trim change after the render is on. Where the two depths look close on paper, the deeper profile is the lower-risk order.

How does an oversill differ from a verge trim at the same depth?

By the direction of the return. An oversill turns down at the front to shed water clear of the wall below an opening, while a verge trim turns up at the back to terminate the system against a fascia or coping. They share colour, length and end caps, do opposite jobs, and are not interchangeable.

Can the profile be cut on site?

Yes, to the measured opening width with a fine-toothed metal-cutting blade, leaving 2–3 mm clearance at each end so the cap seats without being forced. Deburr the cut edge before sealing, so the cap beds against a clean edge rather than catching on a rough one.

Does the projection matter on a sensitive facade?

It changes the proportions of the window detail, so on a listed building or in a conservation area show the profile on elevational drawings and raise it with the local planning authority at design stage. That conversation is straightforward early and awkward once the scaffold is up.