To plan a warehouse racking layout, start with the stock and the trucks, not the racking. Record pallet sizes, weights and heights, measure the building's clear height, columns, doors and floor, choose the truck and its aisle width, then fit runs and beam levels around those fixed points and have the drawing checked for fire routes, pedestrians and floor loads.

A layout drawn the other way round, racking first, usually ends up with aisles that the trucks cannot use or runs that block an exit. The steps below are the order we work in when we draw a layout for a quote.

Step 1: what do you need to know about your stock?

The layout starts with five facts about your stock: pallet plan size, loaded height, heaviest weight, the number of product lines and how many pallets move in and out each day. Those five numbers decide whether you need selective racking, where every pallet is accessible, or a denser system that trades access for space.

A site with hundreds of lines and one or two pallets each needs selective access to every pallet. A site with a few lines and many pallets of each can use drive-in, push back or pallet live racking, which our guide to drive-in, push back and pallet live racking compares. Most warehouses end up with a mix: selective adjustable pallet racking for the long tail and a dense block for fast, high-volume lines.

Step 2: what should you measure in the building?

Measure everything that the racking must fit around. SEMA's installation guide says a good supplier should visit the site before installation to measure floor capacity and height and to analyse stock and picking methods (SEMA, Guide to storage equipment installations). We use the same list whether we visit or work from your drawings.

Layout input	What to record	Why it matters
Clear height	Height to the lowest obstruction: sprinklers, lights, roof steel, heaters	Sets the top beam level and the number of levels
Column grid	Position and size of every column and its base	Runs and flues are lined up with columns to avoid losing aisles
Doors and docks	Position, width and use of each door and dock leveller	Fixes where aisles and the main cross aisle go
Fire exits and routes	Exits, escape routes, hydrants, alarm points	Must stay clear and reachable
Floor slab	Thickness, reinforcement, joints, cracks, drains	Base plate loads and anchor positions depend on it
Trucks	Make, model and data sheet, including lift height	Sets aisle width and maximum beam height

The floor is the item most often skipped. Heavy bays put large point loads through small base plates, and anchors must avoid slab joints. If you have no slab information, a core sample is usually cheaper than a problem found after installation.

Step 3: how does the truck choice change the layout?

The truck decides the aisle width, and the aisle width decides how many runs fit across the building. Our guide to warehouse aisle widths for each forklift type gives typical figures. To show the effect, we took a worked example: a clear area 30 m wide and 40 m long, 1100 mm frames, 2700 mm beams, a 4 m cross aisle at one end and four beam levels above the floor.

With 3.8 m counterbalance aisles, eight rows of racking fit across 30 m. Reach truck aisles at 2.9 m fit ten rows, and 1.8 m very narrow aisles fit fourteen. In this example the very narrow aisle layout holds about 75% more pallets than the counterbalance layout at the same height, before allowing for the extra height VNA trucks can usually reach. It also needs guided trucks and a flatter floor, so the comparison is a starting point for costing, not a verdict.

Step 4: which way should the runs go, and how many levels?

Runs normally go parallel to the longer side of the building, so there are fewer, longer aisles and less space lost to aisle ends. Then adjust the pattern so that columns fall inside the back-to-back flue or within a run, not in an aisle, and so that the main aisles line up with the doors and docks that feed them.

Next, fix the beam levels. Each extra level adds a full layer of positions, as long as the clear height, the truck's lift height and the frame capacity allow it. In the reach truck version of the worked example, 120 bays at three pallets per level gain 360 positions with each level.

Beam level spacing comes from the loaded pallet height plus a top clearance and the beam depth, and BS EN 15620:2021 sets the clearances that apply (BSI, BS EN 15620:2021). Our guide to UK pallet racking dimensions explains the typical figures.

Step 5: where do people, cross aisles and fire routes go?

Plan the routes before the racking fills the floor. The Workplace (Health, Safety and Welfare) Regulations 1992 require a workplace to be organised so that pedestrians and vehicles can circulate safely, with sufficient separation where they share a route (legislation.gov.uk, regulation 17). HSE's workplace transport guidance recommends separating pedestrians from vehicles and using one-way systems where possible (HSE, Workplace transport).

In practice, that means a marked walkway from the staff entrance to offices, welfare and picking areas that does not run down truck aisles; cross aisles so that trucks are not driving the full length of every run; and escape routes that stay open and signed. The Home Office guide to fire safety risk assessment for factories and warehouses is the reference for escape routes and storage arrangements (GOV.UK), and your insurer or sprinkler designer may set flue space widths.

Step 6: what safety features go on the drawing?

The drawing should show the safety items, not leave them to the installer. That means a load notice position for each run, a rack end barrier on every run end that faces a cross aisle, upright protection where trucks turn, and back-to-back row spacers. Where people pick by hand next to pallet racking, add mesh cladding or anti-collapse mesh at the back of the bay as the risk assessment requires.

HSE guidance in HSG76 expects racking to be installed by competent people following the manufacturer's instructions, and to be inspected on a regular, tiered basis (SEMA, HSG76 summary; HSE, HSG76). Planning access for inspection, such as space to walk the runs, is part of a good layout.

Step 7: how do you check and approve the layout?

Treat the drawing as the contract between you, the supplier, the installer and the truck supplier. BS EN 15629 gives guidance on specifying racking and shelving, including how to coordinate suppliers and define each party's responsibilities (BSI, BS EN 15629). A good layout drawing shows dimensions to the building, aisle widths, beam levels, bay loads, protection and notices.

Send it to the truck supplier to confirm the aisle, to your insurer if sprinklers are involved, and to the installer before ordering. If you want to see how we take a project from first drawing to delivery, read how we work; for high-volume lines, our high-density racking range covers the denser options.

Frequently asked questions

How do I start planning a racking layout?

Start with stock data and a building survey: pallet sizes, heaviest weights, loaded heights and daily movements, then clear height, columns, doors, fire exits and the floor. The truck and aisle width come next.

Which direction should pallet racking runs face?

Usually parallel to the long side of the building, with aisles lined up to the doors and docks that serve them. Columns should fall inside a flue space or a run rather than in an aisle.

How many cross aisles does a warehouse need?

It depends on run length, travel distance, escape routes and your fire risk assessment. Long runs without a break increase travel and can lengthen escape routes, so most layouts include at least one main cross aisle.

Do I need a site survey before ordering racking?

It is strongly recommended. SEMA advises that a supplier should check floor capacity, height, stock and picking methods before installation, and many problems only show up on site.

Sources

• SEMA: Guide to storage equipment installations
• SEMA: HSG76 warehousing and storage
• HSE: HSG76 Warehousing and storage, a guide to health and safety
• HSE: Introduction to workplace transport safety
• legislation.gov.uk: Workplace Regulations 1992, regulation 17
• GOV.UK: Fire safety risk assessment, factories and warehouses
• BSI: BS EN 15629 Specification of storage equipment
• BSI: BS EN 15620:2021 Tolerances, deformations and clearances