When hurricane season approaches, the last thing you probably think about is protecting your shed. Yet when high winds hit, sheds are usually the first to blow their tops and collapse. Many of us store some valuable things in our shed, so why not follow a few simple steps to hurricane proof your storage shed?
Building a shed to withstand gale-force winds and torrential rain does not require much investment beyond what you would typically spend to build a shed. Creating a solid shed foundation, and securing the roof, will help your shed survive the next storm.
The best way to build a hurricane-proof storage shed is to start from the bottom, and work your way up using lots of fasteners as you go:
- Build a hurricane-proof foundation
- Secure floor frame to the foundation
- Build strong walls
- Install storm-resistant windows and doors
- Use storm shutters or shields to protect inside of shed
- Construct a wind and waterproof roof
- Important Considerations When Building a Hurricane Proof Shed
- Materials for Hurricane Proof Sheds
- Build Your Hurricane-Resistant Foundation
Important Considerations When Building a Hurricane Proof Shed
A hurricane-proof shed is a bit of a misnomer. There is no such thing as a “hurricane-proof” shed. High winds and epic amounts of precipitation will find even the tiniest weakness in your structure.
There are tons of examples of joists, beams, bolts, studs, and more ripped right from their concrete anchor. In some cases, bolts themselves have wiggled their way loose from concrete pads and piers.
Designing your shed to withstand winds of great magnitude is possible. The goal is to send all outside forces acting upon the structure to the foundation, which is the strongest point of your shed. To do this, every point of your structure above the foundation must be thoroughly fastened in a consistent pattern.
Shed Building Codes
As with any building project, you must first consult your local building codes to determine an appropriate plan for your storage shed. If you live in the state of Florida, which is likely if you are reading this guide, then you’ll find this site helpful. Florida shows plans from various manufacturers of sheds that are rated for high-velocity winds.
Florida mandates that structures, including storage sheds, should anchor to concrete via bolts. As well, they require a host of fasteners on all parts of the wall and roof structure that makes the entire building completely connected. This reduces the likelihood of one part of the building collapsing during high winds and compromising the rest of the structure.
Locating your Shed
Choosing exactly where to site your storage shed might be easy if you don’t have much yard space. Code mandates it must be a certain distance from your home, and most folks opt for a nice, flat corner of the yard.
Considering wind is an issue. Placing your shed beneath a giant live oak branch is not a great idea, or below a power poll, if applicable.
If you live in a dense neighborhood, then all the other structures around will provide a decent windbreak. If not, try and situate your shed to take advantage of any sort of natural barriers that might dissipate huge gusts of wind.
Designing your Hurricane-Proof Shed
Many shed designs can be made hurricane-proof. Thanks to superior fastening technology available for purchase at any big-box home reno store, you can even modify an existing shed to withstand hurricanes. But if you are building new, then there are tons of interesting shed designs that can withstand extreme storms. Here are a few:
- Quonset sheds – purchased as kits from various manufacturers, these sheds are held up by metal arches. The curved design eliminates weak points in the structure, making them ideal for high wind applications.
- Shipping containers – many manufacturers now outfit old shipping containers for use as sheds and even homes. They are heavy – a 10’ container is nearly three thousand pounds! Therefore, a container is built to withstand serious wind and rain.
- Prefabricated sheds – you’ve all seen a motley lot of sheds in the Home Depot parking lot. For the most part, these would get swept into the heavens during a hurricane. However, manufacturers in hurricane heavy states design prefabricated sheds that meet local high wind codes.
- Concrete block shed – if you want to be a hundred percent certain your shed will stay anchored to the ground no matter what, then a cinder block shed is for you. Picture the foundation of your home but as a shed. Expensive and labor-intensive, this is an option for some.
The type of structure you choose won’t matter unless your foundation is solid. A concrete slab or concrete piers are a must for a hurricane-proof storage shed. If you’ve never poured a slab before, check out how to make one here.
All slabs must be reinforced with rebar to meet high-velocity wind zone codes. As well, using backfill to elevate a slab is not a good idea, particularly in flood zones. The fill will erode, compromising your structure.
Piers are another option. Warm climates such as Florida only require 16” concrete footings. The diameter of piers should be no less than 8” more than the width of the walls of your shed.
A storage shed on piers is an excellent option if you are close to an area that is prone to flooding. A slab cannot be elevated like concrete piers and the piers are less susceptible to flooding and wave action because of their small surface area.
Thanks to some new research from architecture professors in New Jersey, ideal types of roofs for hurricane-proofing have been identified. The more you can break up your roof surface area, the better.
Thus, a single slope, slant-style roof is not a good idea. A simple gable roof with a 30° slope is ideal. A hip roof, or one end with a hip, is also appropriate.
Watch out for large overhangs. Roofs that extend beyond walls more than a foot will be susceptible to “uplift” – wind that picks up the roof or structure and deposits it elsewhere. Uplift is not good. Fastening the roof to the walls and adding a central column to anchor the middle center of the roof to the foundation is also a good idea.
Materials for Hurricane Proof Sheds
Building a shed is straightforward, but outfitting it to sustain the force of extreme wind and, possibly, water is a whole different story. See below for special materials you need to hurricane proof your storage shed.
Starting with the foundation, you are going to need a minimum of 3,500 psi concrete. A regular bag of Quickcrete is, on average, around 4,000 psi. You can purchase a 25kg bag of Quickcrete 6000 psi that is fiber reinforced, but it will cost you more. A hurricane-proof shed foundation will need:
- Enough bags of concrete for a minimum 4” thick concrete slab (or piers)
- Steel rebar or mesh, or use fiber reinforced concrete
Your structure rests on your foundation and is bolted to the slab. You will be using a variety of fasteners to bolt the structure to the slab, fastening studs to one another, and attaching the walls to the roof.
- Titan HD Anchors – bottom plate to concrete
- Galvanized L-bolts – sunk in concrete and bolted to the bottom plate with galvanized washers and nut
- Simpson H2 ties – studs to the bottom plate and top plate
- 20 gauge – or less – steel strapping to connect studs, sill plate, and top plate
- Simpson H2A connectors – rafters to the top plate and wall studs
If you are using concrete piers, then you will need 4×4 SYP beams, or two 2×6 PT boards staggered and laminated with HD galvanized nails. Otherwise, standard lumber for building is recommended.
- PT studs for bottom plates
- ¾” PT plywood floor sheathing
- 7/16” OSB sheathing for walls
- 19/32” plywood roof sheathing
- Standard SPF studs for walls and trusses, if applicable
You can purchase pre-engineered roof trusses in any length, but a far more cost-effective solution is to build the roof yourself. As long as you use appropriate fasteners and dimensions, then a hurricane-proof shed roof is completely do-able. Here is what you’ll need:
- 3”x5” metal gussets
- 2”x4” studs for each part of the truss
- Doubled LVL beam to connect both sides of the gable, if applicable. This beam would act as the center beam in your gable.
Build Your Hurricane-Resistant Foundation
Now it’s time to build your hurricane-proof storage shed. Let’s start with the foundation. We are assuming you are anchoring your storage shed to a concrete slab.
- Prepare your foundation. Remember, backfill is not up to code in Florida, where lots of rain or flooding will wash your shed away. Use 21A aggregate to prep the ground beneath your slab, and put a 6mil plastic barrier beneath that to avoid moisture rising from the soil.
- Once you’ve filled and made your form for the pad, it’s time to lay rebar. Use rebar chairs and a grid pattern when installing rebar. Alternatively, you can use fiber-reinforced concrete like this and avoid rebar altogether.
- Be sure to install HD galvanized L-bolts along the perimeter of your foundation. You’ll need one within at least 12” of each end. They shouldn’t be less than 6’ apart, and 4’ is probably best. Use an anchor bolt holder, which attaches to your concrete form, to level and place the bolts.
Secure Shed Floor Structure to Foundation
One of the keys to proper shed anchoring is ensuring the base of your walls do not rot or sustain water damage. Water corrodes fasteners and weakens the overall structure. Here is how to properly secure a hurricane-proof shed to a foundation:
- Use 2”x4” PT studs as a bottom plate for your walls. Your walls will bolt on through the L-bolts embedded in the foundation via the bottom plate.
- When bolting your walls to the L-bolt, consider using a hold-down anchor like this. You’ll have to ensure your L-bolts are placed immediately adjacent to studs, so the anchor fits the bolt and is right next to a stud.
- Use Titen HD anchors to anchor the bottom plate to the foundation further. Place at least every 4’ apart.
Build Strong Walls
Strong walls are crucial when building a hurricane-proof storage shed. Once your walls are connected to the foundation, there are ways you can add strength without much extra cost. Here are some things to remember when building hurricane-resistant storage shed walls:
- Make sure your walls are a maximum of 16” on center.
- Use 7/16” OSB sheathing – plywood is also acceptable but studies show that OSB is stronger.
- Install Simpson CS20 strapping across each wall. Begin at the top and bottom of one corner and run diagonally until you reach the top and bottom plates on the other end. Nail strapping to each stud. For walls with doors, run one strap on either side of the door, unless the door is at the end of one side.
- The type of siding you choose is more of an aesthetic choice. Vinyl siding is an affordable choice that, when installed properly, is not susceptible to high winds.
Install Storm-resistant Windows and Doors
Storm-resistant windows and doors are critical if you are hurricane-proofing your shed. After all, why hurricane-proof if your windows and doors are just going to break and let all the rain in?
If your storage shed has windows, expect to pay more for a window made to withstand high winds and projectiles. High-impact resistant windows have two panes of glass, between which is a plastic film.
These combine to make a highly indestructible window. Remember, the wind itself isn’t the only concern during a storm – it’s also all the junk the wind picks up that could smash into your shed like a tree branch or the neighbor’s lawn ornament.
Another consideration is the drop in pressure a storm creates. The outside is much less pressurized than inside your shed. If something breaks a window, then the resulting wind influx into your shed can seriously mess things up.
Both hurricane doors and windows should have aluminum frames. They are the strongest option, as opposed to fiberglass, vinyl, or PVC. They don’t rust and can withstand impacts that storms might produce.
Storm Shutters and Shields
Hurricane storm shutters are accordion-style shutters bolted to the outside of your shed window or door. They move on tracks horizontally across the window when cranked from the inside. Once closed, they completely protect the window or door.
Usually made from metal or strong polycarbonate material, these shutters come in a variety of sizes. They cost around $20 per square foot. If you only have one or two windows or doors in your shed, they are worth the investment.
You can also purchase roll down types, which feature a large box above the window that rolls down over the window or door.
If you don’t like the idea or cost of permanent shutters, a cheaper option is installing permanent bolts to attach plywood onto in the event of a storm. Installing a length of ½” stainless rod through the studs and into the exterior of the shed will allow you to attach plywood without damaging the frame of the window with nails and screws.
Building a Windproof Roof
As mentioned above, a multi-faced roof will reduce wind shear, as each face will offer less wind resistance than one large, solid face such as you’d find on a slant-type roof. A 30° slope for a standard gable roof is adequate.
Including a hip on one or both sides is even better. Whichever style of shed roof you choose, be sure it is properly secured to your structure.
Constructing a shingle roof in a high-velocity wind zone is not a good idea, in my opinion. If you go to Florida, you’ll see that all the roofs are metal.
This is for a good reason, as asphalt shingles love to go for a ride during high winds. Here are some key points to consider when installing a windproof roof:
- Opt for a steel roof system that screws straight into your OSB roof sheathing. Most metal roof manufacturers will have a recommended high-velocity wind screw pattern.
- Use waterproof underlayment on your roof. Some synthetic underlayments will not self-seal screw and nail holes. If this is the case, use 1”x4” battens on your roof, nailed at every rafter, to attach your metal roof to after you’ve installed the waterproof underlayment.
- Use Simpson H1 fasteners to connect rafters, and H2.5 or H2A connectors to fasten the rafters to the top plate of the structure.
The next time the storm of the century approaches, I hope that you will rest easy knowing your lawn tractor and gardening tools won’t be flying off into your neighbor’s yard.
Using the right fasteners and building techniques to hurricane-proof your house will ensure a stable structure for years or even decades. As always, if you liked this article feel free to share it and add your comments, below.