Irish Ramp Gradients: TGD K & TGD M (Dwelling Approach)

The requirement

Ireland does not set one ramp number. It sets two, in two documents. TGD Part K caps a general ramp at 1:20, never steeper than 1:12 (par. 1.2.1). TGD Part M covers the approach to a new dwelling. Its bands: 1:20 up to 10 m, 1:15 up to 5 m, 1:12 up to 2 m (Table 2, par. 3.1.2.4).

So get the right document before you read off a gradient. Which one you need depends on what the ramp is for. Both use the same 1:20-to-1:12 range. But Part M ties the slope to how much run you have.

Part K: the general ramp. This is for an internal or minor structural ramp. The slope is no steeper than 1:20 (par. 1.2.1). A single flight up to 10 m long may run steeper than that. Even then it must never go past 1:12, whatever its length. A general ramp also needs four more things.

• Clear width of at least 800 mm (par. 1.2.4).
• Clear headroom of at least 2000 mm (par. 1.2.2).
• A handrail at 900–1000 mm. One side if the ramp is under 1000 mm wide. Both sides if it is 1000 mm or wider (par. 1.2.5).
• A level landing at the top and the bottom. Each is at least as long as the ramp is wide (par. 1.2.6).

Part M: the dwelling approach route. This covers the approach route to the entrance of every new dwelling. Here the slope limit depends on the going length. The shorter the run, the steeper you may go.

(Table 2, par. 3.1.2.4.) The approach route needs its own extras too.

• Landings at least 1200 mm long (par. 3.1.2.4). The run between landings is capped at 10 m on the 1:20–1:15 part. It is capped at 5 m on the 1:15–1:12 part.
• Clear width of at least 900 mm and clear headroom of at least 2100 mm (par. 3.1.2.1).
• A handrail at 900–1000 mm on a flight, and 900–1100 mm at a landing (§1.1.3.6).

Which one applies? Building the step-free route to a new house’s front door? That is TGD M. Building a general or minor ramp somewhere else on the job? That is TGD K. Think a shed ramp, or a change of level inside. The two documents share the same range. But do not assume they give the same answer for the same rise.

Work it out on site

You are building the TGD M approach route to a new dwelling’s front door. The threshold sits 450 mm above the path. How long does the ramp need to be?

1. Try the flattest band first. TGD M allows 1:20 for a going up to 10 m. 450 mm × 20 = 9000 mm, so 9 m of run. That is under the 10 m limit, so it fits.
2. Check the steeper bands. The 1:15 band only covers a going up to 5 m. At 1:15, this rise needs 450 × 15 = 6750 mm (6.75 m) of run. That is over the 5 m limit, so 1:15 is out. Same story for 1:12, which stops at 2 m. So this ramp runs at 1:20.
3. Add the landings. A landing at least 1200 mm long goes at the top and at the bottom.

So: about 9 m of ramp at 1:20, with 1200 mm landings at each end. The slope calculator does the rise-over-run and the band check for you.

Do it in 5 seconds

Related

• Part of the Irish Building Regulations hub — the hub, with the TGDs that set the rules.
• Building the stairs that ramp might replace? See Irish stair & barrier rules.

Sources

• TGD Part K (2014) — Stairways, Ladders, Ramps and Guards, par. 1.2.1 (general ramp slope), par. 1.2.2 (headroom), par. 1.2.4 (width), par. 1.2.5 (handrail) and par. 1.2.6 (landings). Read it at gov.ie.
• TGD Part M (2022) — Access and Use, Table 2 and par. 3.1.2.4 (dwelling approach gradient bands and landings), par. 3.1.2.1 (width and headroom) and §1.1.3.6 (handrail heights). Read it at gov.ie.

Read this first. TGD K figures above are from the 2014 edition, in force since 1 January 2015 — an older 1997/2005 edition of TGD K still circulates online with different numbers, so confirm you’re reading the current one. TGD M figures are from the 2022 edition, in force since 1 January 2024. Both are deemed-to-satisfy routes, not the only legal ones, and both carry transitional arrangements — the edition in force can vary by the commencement or permission date of your job. Always confirm the current edition on gov.ie before you build to it.