18 x New 20ft Topper Units Delivered to a Self Store Site

We recently supplied an expanding containerized Self storage site with eighteen ‘topper’ 20ft containers to be situated on the sites upper level. We modified 18 x 20ft 1 trip RAL 5013 containers to create these topper units at our East London depot. These were then all delivered over a 2 day period to the site using flat bed and HIAB crane trucks.

What is a topper container?

A topper unit is essentially a 20ft container with a 4ft wide corridor created in the middle, with two 8ft sized storage units then being created within the container. This is done by cutting out 4ft wide sections of the containers side panels, to then open up the sides and allow for a corridor to be formed. Steel partition walls are then fitted to the corridors to create the 2 x internal storage units (1 on each side). Steel high security Kirncroft style doors are inserted into the partition walls to gain access to each small storage unit.

Why is a topper container a good storage solution?

Maximizing self-storage revenue is a key area for sites to focus on as part of their business plan/growth strategy. Once a self storage site has filled its ground level units, and it cannot expand outwards on the ground level, the only way to go is up in this instance. 

Upper level storage containers are less favorable for some users as they cannot offer ‘drive up’ access with a vehicle. For those needing to access the unit regularly, ground level units are preferred. People also don’t want to lug large items of personal goods up and down stairs. Mobile stairs are often used to access upper level units.

Topper containers however offer a different solution.

With the corridors running the entire length of a row of upper level topper units, with fixed steel staircases positioned at one or either end of the walkways. The walkthrough corridors allow for ease of use and access to each individual storage unit. Often sites now offer trolleys to help move goods along the passageways with ease. We have seen at some sites that install automatic motion sensor lighting which can be activated along the internal walkways to ensure the units are lit up efficiently when customers walk through.

Some things to think about when ordering your topper:

Fixed end vs open ended corridor?

One thing to think about, based on the layout of your site, is if you want stairs at both ends with a corridor going all the way through. The other option, as per the photo below, is to close off the corridor by fixing a steel mesh fixed panel. This can then be later removed if the site decides to add more topper units or position stairs at the end.

Flooring Type

You can choose between standard container floor (FSF easy clean flooring) or metal plated floor with engrained tread (recommended).


You will want to make sure the topper units match your ground level units, so make sure to choose the same RAL paint colour when ordering!

Container Twistlocks

We strongly recommend using ISO container interlocks to securely position the toppers on top of the ground level 20ft container. These steel interlocks securely fasten the upper and lower units together perfectly in line into the corner castings.


Get in touch with our team today to discuss your topper container requirements, a long with any other container requirements you may have!

Get in Touch