Description
External wall insulation pushes the wall face outwards, and the original sill ends up tucked behind it. The Over Sill Anthracite 2.5m 170mm Depth covers that old sill and takes a dark edge back out past the new render. It is the third of four anthracite depths: 170 mm deep, 2.5 m long, one step short of the deepest.
Four Reasons to Look at 170 mm
- Room on both sides. With 140 mm below it and 220 mm above, a change in your site figures still leaves a neighbouring depth to move to.
- 2.5 m in a single piece. Each length is cut on site to the width of the sill it covers.
- A dark sill for dark frames. Anthracite pairs with the anthracite verge trim along the top of the same wall.
- A matching colour twin. The same 170 mm depth is listed in white.
The Over Sill Anthracite 2.5m 170mm Depth: Key Facts
An oversill is laid over the existing sill: a flat board, a short upstand at the back edge and a turned-down front edge. The photo on the product shows this outline with caps fitted; it is shared by the four anthracite depths.
| Property | This over sill |
|---|---|
| Colour | Anthracite |
| Depth | 170 mm, third of four |
| Length | 2.5 m |
| Outline | Flat board, back upstand, front edge turned down |
| End caps | Sold on their own: anthracite end cap pair |
| Colour twin | White over sill, 170 mm |
Depths and Colours Side by Side
Go across from your depth to your frame colour.
| Depth | Anthracite | White |
|---|---|---|
| 110 mm | Anthracite 110 mm over sill | White 110 mm over sill |
| 140 mm | Anthracite 140 mm over sill | White 140 mm over sill |
| 170 mm | This over sill | White 170 mm over sill |
| 220 mm | Anthracite 220 mm over sill | White 220 mm over sill |
Choosing Between 140, 170 and 220 mm
When two depths both look possible, the deeper one is not automatically the safer buy — the wall decides. Before you order, note at each opening:
- the finished thickness of the insulation and render going on around the window;
- how far the sill you have now projects from the wall.
Call the counter on 023 8200 2442 with both numbers and the depth is fixed before anything is ordered. Windows of different sizes on one elevation are taken one at a time.
How Many Lengths and Caps
Take the width of each sill, divide by 2.5 m and round up.
- A 0.9 m sill: one length, trimmed to fit.
- A 3.0 m sill: 3.0 ÷ 2.5 = 1.2, so two lengths.
- A bay of three separate sills: three anthracite cap pairs, one per sill with two open ends.
If two lengths have to meet on one sill, settle the joint with the counter before you order.
Other Anthracite Trims
- Anthracite verge trim with upstand — the dark profile for the top edge of the wall.
- Anthracite end cap pair — the caps for both ends of a sill or verge.
- All depths and the white family: the window sill extensions page.
Anthracite or White
The frames settle it. Keep dark frames with this sill, the anthracite verge trim and the anthracite caps. For white frames, the white 170 mm over sill in the table has the same depth and its own white caps.
Fitting Guides
- How to install window sill extensions — measuring, cutting and closing the sill.
- Render detailing around windows and doors — where sills, beads and render meet at the reveal.
Ordering, Delivery and Returns
- Dispatch — Renders World processes orders the same day when the stock is there; put the caps in the same basket.
- Delivery — quoted by the team once the order is placed; parcels up to 25 kg go next day and are delivered kerbside.
- Collection — the counter is at Unit 9A, Central Trading Estate, Southampton SO14 5JP: Monday to Friday 7am to 5pm, Saturday 7am to 12pm.
- Returns — within 14 days and in original condition for goods bought directly from Renders World; special orders and promotion purchases are not returnable.
FAQ
What insulation thickness is 170 mm for?
That comes from your wall. Phone 023 8200 2442 with the insulation and render thickness at the window and the current sill projection, and agree the depth before you buy.
Is the photo the 170 mm size?
The photo shows the outline common to the four anthracite depths. You receive the depth in the title, 170 mm.
Is it aluminium or uPVC?
If your specification calls for a particular material, ask the counter on 023 8200 2442 before you place the order.
Are caps included with each length?
No — add the anthracite end cap pair as its own item, one pair for each sill with two open ends.
Can I get 170 mm in white?
Yes: the white 170 mm over sill, closed with the white end cap pair.