Reuben's Home Inspection Blog

head_left_image

Don't Lean On Me - The 500 Pound Requirement For Guardrails

The International Residential Code requires deck guardrails to be present when the deck surface is more than 30″ above the ground.  Guardrails must be at least 36″ high, and must be designed in such a manner as to prevent 4″ sphere from passing through.  This is all pretty easy to build, as long as you own a tape measure.  The last requirement is that guardrails be able to withstand 200 pounds of pressure along the top rail.  Now here’s the kicker - according to some, the guardrail must also be constructed with a safety factor of 2.5.  

Click any of the photos of unsafe guardrails below for a blow-up.

Very wobbly (featured in video below), spacing greater than 4" Flimsy, spacing greater than 4" I don't even know where to start...Flimsy, less than 36" high, spacing greater than 4" Flimsy, spacing greater than 4"

A safety factor of 2.5 means that the guardrail must be constructed to withstand 500 pounds of pressure along the top rail.  This means that guardrails must be constructed to be ridiculously strong, and most methods of conventional contruction aren’t good enough.   A guardrail constructed with 4×4s attached to the deck with lag bolts will actually rip the bolts out of the deck long before 500 pounds of pressure can be applied to the top rail.

DTT2Z bracket made by Simpson Strong-TieThe easiest and surest way to construct a guardrail that will withstand 500 pounds of pressure is to use metal brackets that are designed just for this purpose.   A couple manufacturers that make brackets just for this purpose are DeckLok and Simpson Strong-Tie.   They’re also the ones that promote the safety factor of 2.5 (go figure).  According to reports that I’ve read by both of these manufacturers, metal brackets are the only way to achieve the 500 pound rating.  I’ve talked to deck builders that say there are other ways to achieve this rating, but I’ve never seen any testing reports that verify this.  Nevertheless, most building officials in the Twin Cities area aren’t picky about guardrail details, and they allow guardrails to be built without metal brackets.

To read an in-depth report with several different construction methods and tests, go here.  The only problem I have with this article is that the testing they’re doing is based on a single post, and no guardrail can ever be constructed with a single post.  As soon as other posts and right angles are incorporated in to the guardrail, it will get much stronger.  When I inspect houses and I find flimsy guardrails (like the one in this video), I tell my clients to repair or replace them.  When I find guardrails with 4×4s that have been notched, I tell my clients that the guardrail might not be strong enough to prevent a large, falling adult from breaking it.


Reuben Saltzman, Structure Tech Home Inspections - Email - Minnesota Deck Inspector

RELATED POST: Deck Safety (Balcony Collapse)

 

Reuben Saltzman, Structure Tech Home Inspections

        

Comment balloon 4 commentsReuben Saltzman • June 09 2009 06:34AM
Don't Lean On Me - The 500 Pound Requirement For Guardrails
share
The International Residential Code requires deck guardrails to be present when the deck surface is more than 30″ above the ground. Guardrails must be at least 36″ high, and must be designed in such a manner as to prevent 4″ sphere from… more
A Common Problem With Roof Caps For Bath Fans
share
I start every home inspection by giving myself a quick tour of the inside of the house to get an idea of what I need to be looking for while inspecting the exterior. While doing my brief initial walk-thru of the interior, I also turn on everything… more
Why I Never Recommend Having FPE Stab-Lok Panels Evaluated By An…
share
Federal Pacific Electric Stab-Lok panels have long been known to be problematic, and I've always called them out as a potential safety hazard, but I've recently become much more ‘agressive' with the way I report them. While performing a home… more
Why Boilers Are Better Than Furnaces
share
Whenever I get around to building my dream home and money is no object, I won't be using a furnace for heat. I'll be using a boiler. Gas fired forced air furnaces are the standard for homes in Minnesota, but boilers have definite advantages over… more
How To Look Up Saint Paul Truth-In-Sale of Housing Reports Online
share
The city of Saint Paul is now giving online access to Truth-In-Sale of Housing reports! Like Minneapolis has been doing for the last two years, Saint Paul is now providing easy access to TISH reports online. While the reports won't be 'created'… more
Why Reversed Polarity Is A Hazard
share
Any time I inspect a house where an amateur has been doing electrical wiring in a home, there's a good chance that I'll find outlets with reversed polarity. This happens when the hot and nuetral wires get flipped around at an outlet. Reversed… more
Radon Resistant Construction Is Now Required In Minnesota
share
It’s estimated that one out of three homes in Minnesota has elevated levels of radon gas Because of these high numbers, the Minnesota State Building Code has adopted Apendix F of the International Residential Code, Radon Control Methods. This… more
How To Fix Ungrounded Three Prong Outlets
share
One of the most common electrical defects that I find when inspecting old houses in Minneapolis and Saint Paul is ungrounded three prong outlets. This happens when a standard three prong outlet is wired without the ground wire being connected. … more
Should Real Estate Agents Attend The Home Inspection?
share
Many real estate agents don't attend their buyer's home inspection because someone has told them that this increases their liability. I completely disagree. It's their conduct at the inspection that puts them at risk, not their presence. … more
Why Don't Home Inspectors Mention Code?
share
Home inspections are not ‘code’ inspections, and a lot of home inspectors even treat the word ‘code’ as taboo. They call it the ‘C-word’. I recently had another home inspector on AR tell me he’s not even allowed to use that word in Kentucky. … more