Concealed LED cove light washing a textured plaster wall

You've read Spec 01 · here's what comes next

Architectural
LED Lighting

How to create elevated spaces for a fraction of what they cost.

Once you can specify and install this yourself, the expensive part stops being the lighting and starts being the idea. This is the complete guide to doing that — the numbers that decide each choice, five recess details drawn as construction sections, and a prompt that turns your measurements into a full system spec.

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About twenty minutes to a complete spec · AU/NZ and US editions · yours forever

Who's telling you this

I install this for a living. I learned it from the electricians on my own sites.

I'm Lach Wann. I'm a qualified landscaper and I've been specifying and installing low voltage lighting for years — but I remember exactly what it was like not to know how, and I remember every detail I didn't have until an electrician stood on one of my projects and taught it to me. That's what's in here — the hands-on advice you won't find in a manufacturer's brochure.

40 reviews across the guides I've written before this one, five stars on average. This is my first on lighting, so nobody has reviewed it yet.

If it's not useful, don't pay for it

Read the whole thing. If it doesn't save you more than $29 worth of mistakes, reply to the receipt within thirty days and I'll refund it — no form, no questions, and you keep the guide.

"Lach's Balcony Garden Guide was a game-changer for how I viewed my garden… This guide has helped me so much in framing what are the considerations I need to accept and work within to have a thriving garden."
PSPaul Scarf, Surry HillsBalcony Garden Guide · Mar 2025

"An incredible guide to balcony planting! Formatted in a super digestible way, friendly for a broad range of abilities from beginners to experts. Really concise and informative without being overwhelming."
GGenevieveBalcony Garden Guide · Mar 2025

Get the complete guide — $29 or keep reading

Where Spec 01 left off

Knowing the components isn't the same as knowing your numbers.

The shopping list told you what belongs in the system, and that the brand barely matters. What no list can tell you is how to size any of it, because that part depends entirely on the space you're standing in.

It depends on how long your runs are, how deep your recess is, where you'll see the strip from, and whether the thing you're lighting is a shelf, a ceiling, a bench or a set of stone steps. Those are the four questions the last page of Spec 01 ended on:

01Which driver suits your run lengths.

02Where to split feeds so the far end doesn't fade.

03How deep a recess needs to be before the strip disappears and only the light remains.

04Which detail suits cove light, under-shelf wash, toe-kick or outdoor steps.

This guide answers all four, in the order you need them, with the arithmetic done and the details drawn.

Those decisions are what separate architectural from merely installed.

How you'll actually use it

Three steps, about twenty minutes

You don't read this cover to cover. It's a reference you dip into, and a prompt that does the assembly.

Measure

You've already done this — it's the ten-minute exercise at the end of Spec 01. Count your runs, measure each one, note which are outdoors and where you might see the strip.

Read only what applies

Go to the two or three sections that match your condition. A cove and a toe-kick need different things, and you can safely ignore the rest until you need it.

Paste in the Spec Prompt

Answer six questions, paste it into any AI, and get back a complete specification — strip, driver schedule, feed strategy, dimmer and an order list, with the arithmetic shown.

The prompt is the point, and so is the reading

The prompt writes the spec. It doesn't teach you to judge it, and sometimes it will get something wrong. The reason the guide sits in front of it is so you can tell when that happens — which is the difference between using a tool and trusting one.

See it before you buy it

Nine minutes of the install, free

Every physical connection filmed close up on the bench — driver to feed wire, feed wire to strip, soldering a tail onto bare strip, two runs off one driver, and fitting an extrusion with its diffuser. No email required.

The video shows you how every connection is made. It doesn't tell you which driver your runs need, where to split the feeds so the far end doesn't fade, or how deep a recess has to be before the strip disappears and only the light comes out. That's the guide.

What's inside

The questions it settles

A sample of what you'll stop having to guess at:

There's one number on every strip listing that decides whether your light can finish exactly where your recess finishes. Almost nobody checks it, and it can't be fixed once the roll arrives.

Your driver has to be bigger than the load it carries — but by how much? Undersize it and it dies young; oversize it and you're throwing money away.

The thirty-second test that tells you which wire is which before you commit the joint. Skip it and you'll be cutting apart work you've already finished.

The component most likely to fail in the whole system, and the rule about where you're allowed to hide it. Break that rule and you'll be opening a finished wall in about ten years.

The number on the spec sheet that decides whether your skin looks beautiful or weird under the light. It's the widest quality gap between cheap and good.

An opal diffuser quietly eats a share of your brightness. Know the figure and you allow for it when you order; miss it and the room lands way darker than you designed.

How to double the distance a single run can carry — fewer connections, fewer feeds, an easier install.

Five recess details drawn as construction sections: cove, flush channel, under-shelf, toe-kick and outdoor step nosing. The dimensions are on the drawings. Yours.

The single rule about colour temperature that separates a room you want to sit in from one that feels like a service station. It costs nothing to follow and most people break it.

Outdoors, it isn't the strip that fails — it's the joint. Where the water actually gets in, what a rating that survives really costs, and why the cheap version is one you'll end up digging back out.

Three separate boxes have to agree before a dimmer will work. If one of them doesn't say a particular word, you get flicker — and most people discover that after the wall is patched.

The Spec Prompt: six answers in, a complete compatible specification and order list out. Written so it asks you for anything it's missing instead of guessing.

And where to buy it. One of these components is worth sourcing locally and the rest aren't — get that the wrong way round and you're either paying showroom prices for something you could have had for a third, or waiting three weeks on a shipment you needed on Friday. I lost months assuming the good stuff was trade-only. It isn't, and I'll tell you where I get each part.

Look inside

Two of the five details, in full

These aren't renders. They're construction sections with the dimensions that matter annotated on them, drawn from details I build. Five come with the guide:

01 · Cove uplight 02 · Recessed flush channel 03 · Under-shelf wash 04 · Toe-kick wash 05 · Step nosing, outdoors

Two of them are below, complete and at full size.

WANN StudioPlate 01 · Cove uplightSection · NTS

Bulkhead upstand hides the strip; the ceiling becomes the fitting. The most forgiving detail here: distance does the diffusing, so standard strip is fine.

WANN StudioPlate 03 · Under-shelf washSection · NTS

The 20 mm lip is the whole trick: it hides the source from a seated eye and turns the shelf into a floating plane of light.

Reproduced exactly as they appear in the guide

What you get

Everything, but you only read what you need

Spec PromptSix answers in, a full specification out — strip, driver schedule, feed strategy, dimmer and order list, with the arithmetic shown. Works in any AI you already use.

ReferenceTwelve short sections, one per decision. Written to be dipped into rather than read through — go to the one you need and ignore the rest.

DrawingsFive recess details drawn as construction sections, plus diagrams for the wiring chain, cut points, LED density and the three ways to power and control a system.

Two editionsAustralia / NZ and United States. Different voltages, different rules, different terminology — including the ELV trap that catches US readers following international advice.

VideoThe nine-minute install section, embedded with no ads.

Where to buy itWhich components to buy locally and which to order online, the suppliers I use for each, and a tools and parts page you can work straight down.

UpdatesAny correction or addition I make lands in your copy at no extra cost.

What people said about the earlier guides

Each one labelled with which guide it's about, because a review of a different product is only worth something when you know that's what it is.

"Lach's Guide has been a delightful and surprising experience. Like being gifted with a whole new world of plants… I absolutely recommend his guides for anyone wanting to transform a boring space. Lach is a wonderful communicator too."
ASAlana ShawAn earlier garden guide, now retired · Feb 2025

"Lach's resources are fantastic tools for discovering your ideal garden style… As both a garden owner and designer, I find these resources incredibly valuable."
MMar, SydneyOn the guides generally · Feb 2025

Reviews of this guide will replace these as they come in.

Fit

Who this is for

It's for you if

You've measured your runs and now need to turn them into a spec
You're renovating and want the lighting to look designed, not added
You're comfortable doing careful work with your hands
You'd rather understand the reasoning than follow a parts list

It's not for you if

You want someone to do it for you — that's a commission, not a guide
You're after RGB, app control or party lighting
You want to wire mains yourself without an electrician
You already spec architectural lighting for a living

Who wrote it

Lach Wann

Concealed strip lighting in the WANN House renovation

I design gardens, interiors and whole spaces, and lately I've been renovating my own house in public — filming the parts most people would hide.

This guide came out of wiring that renovation. Everything in it is something I've done with my own hands, got wrong at least once, and worked out a better way to do. The recess details are drawn from the ones I actually build.

I'm not an electrician, and the guide is explicit about where that line sits and what belongs to a licensed one.

Complete Guide 01