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How to Build a Low-Maintenance Garden Storage Shed From Steel Cladding

Eugene has a keen interest in DIY and gardening. Over a 30 year period he has also become self taught in garden power tool maintenance.

building-a-shed-from-start-to-finish

Building a New Garden Shed

Have you ever wanted to build your own garden shed? I always have and attempted my first one when I was about 10 years old, but abandoned the project because of lack of materials, skills and tools! Eventually, 40 years later, I got around to building a proper garden tool shed.

Although quite large, my workshop had become cluttered with garden tools, bikes and other miscellaneous stuff, and I needed more storage space. So it was time to build another shed specially for all this extra equipment. This article is a diary covering the details of construction and might help you if you are considering building something similar.

How Much Did It Cost to Build?

Total cost of materials including the concrete floor was €1500. This is equivalent to about $1800 or £1334 at 2022 exchange rates.

Power Tools Required For Constructing the Shed

I used a lot of power and hand tools and while some power tools were pretty much essential for speeding up work, you can make do. These were some of the ones I used:

  • Miter saw for cutting timber to length. It's advisable to buy one of these.
  • SDS Power drill for boring timber and making holes in concrete for fixing bolts.
  • Angle grinder for cutting sheets of cladding
  • Circular saw for cutting and shaping roof timbers
  • Cordless drill for screwing cladding to timber
  • Halogen or LED worklights if you want to continue working in the evening when days start to get shorter.

You also need general hand tools such as

  • Handsaw for quick cuts
  • Hammer for nailing
  • Level for making sure concrete and the shed are level and plumb
  • Utility knife for cutting underlay
  • Drill bits
  • Rake, shovel, buckets for concreting
  • Measuring tape. 6 m (20 feet) is adequate unless your shed is very long.

Stage 1: Clearing the Site, August 2015

The old shed had long outlived its purpose. Built in the late 40s or early 50s by previous owners, it was a patch work of corrugated iron, flattened out oil barrels and scrap timber, probably sourced from the salvage yard of a local man who used to collect this sort of stuff from demolished buildings. The roof was peppered with pinholes from corrosion and had leaked for years, however no amount of silicon sealant would fix what were now gaping cavities.

Old, corrugated iron shed, in need of replacement.

Old, corrugated iron shed, in need of replacement.

I thought it wouldn't take long to pull the structure down with a hammer and crowbar. However the builders had done a good job, using spiral shank nails to hold the corrugated sheets onto the timber frame. This is probably a lot more secure method of preventing sheet removal by burglars than using TEK screws.

Prying off corrugated iron sheets.

Prying off corrugated iron sheets.

Using a pry bar to remove corrugated iron.

Using a pry bar to remove corrugated iron.

Spiral shank nail.

Spiral shank nail.

Stage 2: A New Year, 2016 and Back to Work on the Project

Cold, wet weather and incessant rain during the autumn and winter of 2015, getting side tracked by other chores and duties and a series of personal events led to abandoning the project for the rest of the year. I eventually got back to clearing the rest of the shed in February. The corrugated iron was bedded down under the concrete floor and had to be prized out with spades, crowbars and cut with an angle grinder.

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Removing corrugated iron with a pry bar.

Removing corrugated iron with a pry bar.

Stage 3: Starting to Concrete

June 1st, 2016

The existing concrete floor was at two different levels. It was partially cracked also and didn't have a vapour barrier which meant the air in the shed was always damp, with lots of condensation on the underside of the corrugated roof on cold mornings, which inevitably dripped down over everything. I decided to break up the cracked section of concrete which resulted in a large pile of rubble. I would also lay a new floor on top of the remaining concrete section, but make it thicker at the edges for structural strength. The new shed would be several feet longer and wider than the existing one. This resulted in having to excavate lots of soil which needed to be spread out over the garden, under trees, into hedges and basically anywhere I could find space.

Marking Out

I roughly marked out the corners of the shed with 1/2" (12 mm) rebar and marking paint. Firstly I hammered two pieces of rebar into the ground to mark the front wall, knowing the length of the planned shed. Then I roughly positioned the 2 bars for the back wall knowing the width of the shed. Knowing the length and width of the shed and using Pythagoras's Theorem, this gave me a measurement for what the diagonal length should be between opposite corners. This established the footprint for the shed.

Stage 4: Dealing With a Particularly Temperamental Cement Mixer

The Belle mixer had been thrown out but rescued several years ago from a scrap yard. It was minus a stand so I built a new tripod out of 1 1/2 inch gun barrel, 2 inch box, a short piece of round solid bar and some flat steel. It didn't have an engine either. Modern Belle mixers are usually driven by a Honda or Robin engine but I decided to use the engine from my old Suffolk Punch cylinder lawn mower as a replacement. But little did I know what hardship was ahead of me! The float bowl on these engines tend to drip eventually, but because the engine was mounted at a 45 degree angle on the drum, the bowl was never vertical, so the float never sealed properly. The result was lots of petrol drips during mixes. Next problem was the drive belt started slipping during a mix, with another mix ready in the wheel barrow and a third mix spread out on the ground! Very frustrating! Eventually the engine stopped working and refused to crank. I opened it up and discovered that the splasher on the crankshaft had broken off. So the engine was running dry with no lubrication. This damaged the connecting rod and smeared aluminium over the crank shaft. I made a new splasher, but eventually when the concrete floor was almost complete, a large bang signalled that my 'trustworthy' engine had definitely reached the end of its life this time. A post mortem revealed that the connecting rod had broken up into 5 pieces. The last section of concrete had to be mixed by hand.

My Belle cement mixer with homemade tripod.

My Belle cement mixer with homemade tripod.

Stage 5: Building the Formwork and Laying Concrete

Building the Formwork

I decided to lay concrete in six sections. I used two-by-fours (2 x 4) for the form work (the timber "shuttering" or mould into which concrete would be poured). This shutter consisted simply of a rectangle, nailed at the 4 corners. For the long walls, 2 x 4 had to be joined with short 2 x 4 scraps because the lumber wasn't long enough to extend the full length of the side. At the corners, nails weren't driven home so that the formwork could be easily disassembled later with a crowbar without damaging the concrete it surrounded. Thinner boards can be used instead of 2 x 4, but 2 inch thick timber requires less pegs to hold it in place because it doesn't flex and bow as much over a long span.

What's a two by four?

A two-by-four, (2 x 4) or four-by-2 in the UK (4 x 2) is a piece of rough, unplaned lumber (wood or timber) with a cross-sectional area of approximately 2 inches x 4 inches (also written as 2" x 4", the quotes meaning inches). Typically these are available in lengths from 4 feet to over 20 feet long. It's a popular size, used for constructing stud walls (framing), bench frames and other general construction. In countries that use the metric system, these are sometimes a bit thinner than 2 inches. (44mm by 100mm).

Getting the Formwork Square

With the formwork constructed in place and two rebar pegs hammered into the ground to mark the endpoints of the front wall of the shed, I dragged the frame into position so that its two end corners coincided with these pegs. Then knowing the width and length of the shed, I was able to calculate what the diagonal lengths should be using Pythagoras' Theorem. Using two tapes stretched between opposite corners of the formwork, I altered its shape until the diagonals were equal. This is pretty much essential if you want the footprint of your shed to be rectangular and not skewed. If you don't do this, you'll run into problems later with everything off square and for example, roof sheeting will be crooked. I then hammered rebar into the ground to mark the two back corners and tied the four corners of the frame to the four pieces of rebar. Next I hammered pieces of 2 x 1 at 6 foot intervals into the ground and after levelling the formwork, nailed it to these pieces. This prevented any sideways or up and down movement.

Use Pythagoras' Theorem to calculate the length of the diagonals.

Use Pythagoras' Theorem to calculate the length of the diagonals.

Laying Concrete

I had kept the existing floor from the original shed and used this as foundation. However if you intend to lay a floor, you need at least 4 inches of sub-base rubble to act as a foundation, topped with sand to stop the stones piercing the moisture barrier plastic. The ground is dug out beforehand so that this sub base is flush with the ground. 4" (100 mm) of concrete is plenty strong for a garden shed with no vehicular traffic, but 6" (150 mm) is the minimum for concrete that is going to be driven on.
1200 gauge polythene sheeting was used under the concrete as a moisture barrier. This makes for a really dry shed. If you don't use a damp proof barrier, moisture rises through concrete and on a frosty day it can condense on everything. The floor was constructed in six, 1m (approx 39") wide strips.

Formwork in place and first slab of concrete laid.

Formwork in place and first slab of concrete laid.

New slab of concrete.

New slab of concrete.

New concrete floor in place.

New concrete floor in place.

Stage 6: Erecting the First Wall

Walls were constructed from 2 x 4s. Treated 2 x 4s were used for the bottom plates in contact with the concrete. I nailed on 4" damp proof membrane with galvanized slab nails to give the timber additional protection from rising damp that could cause wet rot. It's recommended that studs are spaced 16" (40cm) apart for sturdy construction. 4" (100mm) round wire nails were used for nailing the studs to the top and bottom wall plates, a pair for each stud, top and bottom.

First stud wall constructed.

First stud wall constructed.

Damp proof membrane was nailed to the underside of the treated timber as added protection against wet rot.

Damp proof membrane was nailed to the underside of the treated timber as added protection against wet rot.

First stud wall erected.

First stud wall erected.

  1. Cripple
  2. Window header
  3. Top plate / upper wall plate
  4. Window sill
  5. Stud
  6. Bottom plate / sole plate / sill plate

Stage 7: Erecting a Second Wall

All work was done single handedly and while walls were not excessively heavy, some thought had to be put into rising them into place. Quick release clamps placed at strategic locations at arms reach allowed me to clamp on lengths of 2 x 4s to act as stays to keep the walls in place. Once this was done, the stays could be nailed into place to make them more secure.

Second stud wall in place.

Second stud wall in place.

Stage 8: Four Walls in Place

Four walls erected and ready for top plates. Notice the 1 x 2 diagonal braces. These were added to keep everything square. Should have cut the overhanging apple tree first. Removal was a bit awkward to avoid demolishing the walls!

All four stud walls in place.

All four stud walls in place.

Lowering cut limbs from the overhanging apple tree.

Lowering cut limbs from the overhanging apple tree.

Should have cut this apple tree before construction!

Should have cut this apple tree before construction!

Tree trimmed back.

Tree trimmed back.

Stage 9: Adding the Roof

Once the top plates were in place, it was time to build the roof. On advice from carpenters on a building forum, I decided to use 2 x 7s for rafters. Snow load can potentially amount to tons of weight on a roof. Birdsmouths were cut using a circular saw and reciprocating saw and waste chopped out with a chisel. Rafters were then toe nailed to the top plate at the front and back walls. Toe nailing means skewing the nails or hammering them at an angle so they're less likely to pull out.

Two plates added.

Two plates added.

Birdsmouths or notches had to be cut out of the ends of the rafters to allow them to rest on the top plates.

Cutting birdsmouths.