March 8th, 2009

So!  Today I heard the guys in the office talking about “yet another Dry Weather Building”. 

Take note of “the guys”.  You’ll hear a lot about them over the next few months.  … but I digress!

“What’s a Dry Weather Building?”  I hear you ask.  That’s not surprising, ’cause that’s just what I said.

Turns out that the big chief – that’s Phil Emmerson to you and me – had been out to see a customer complaining that rain water was getting under his roller shutter door and into the building.

As soon as he saw the doorway with the roller shutter and the nice little puddle of water extending 5 or 6 feet inside the doorway, Phil new what the problem was and concluded: Dry Weather Building!  

The roller shutter was fitted and working correctly.  The bottom rubber was making good contact with the floor across the width of the doorway. 

The concrete floor was the problem.  It had been formed at the same level on both sides of the doorway but had ended up with a very slight downward slope from the outside to the inside of the building.  In fact, Phil concluded that rain water would still have run into the building even if the floor had been perfectly level across the threshold.

I asked him to explain…

“Consider the lily.”  He said.  Oops!  Sorry!  That’s me drifting off into Life of Brian again.  Brian works in our production office, by the way.  Pretty sure it’s a different Brian though.

No!  “Consider this…”  He said, and went on to explain…

Vertically opening doors such as Roller Shutters and Sectional Overhead Doors have no physical threshold to prevent water running into the building when the door is open. 

… and when the door is closed the effectiveness of any bottom seal is dependant on the condition and profile of the concrete floor across the opening.

Even with an effective bottom seal and seemingly level floor, rain water can pool against a door and may run into the building as soon as the door is opened for access.  And let’s face it.  Most loading bay doors, for example, spend as much time open as they do closed.

The door is only one part of the equation, however.  The construction of the building floor and threshold are just as, if not more, important.  If these are not correctly formed so that rain water is directed out and away from the building then no matter how well the door is sealed when closed, once the door is opened water will run in, so what you have is a “Dry Weather Building”

There are many ways that a building doorway and threshold can be formed to prevent this problem.  These range from solutions as simple as making sure that the floor slopes down and out of the building to installing a drainage channel to take away the water.  The latter being an effective solution for a garage doorway at the bottom of a downhill driveway, for example.

Having recognised this phenomenon of “Dry Weather Building” as an all-too-common problem we have produced one of our “Useful Information” documents giving details and diagrams of several suggested threshold details for door openings.

Although many of these solutions can be “retro-fitted” to existing openings, we strongly advise anyone involved in a new development or building extension project to check with your architect and builder to ensure that this problem has been taken into consideration during the design stage.

Anyhow!  This is my first blog and that’s enough of my ramblings for now.  I’d like to know what you think – good or bad – so post a reply or email direct to blog@emmerson-doors.co.uk

Visit our main website at www.emmerson-doors.co.uk.

For further advice on this issue or any other, please contact our technical team on 01977 685566 or email technical@emmerson-doors.co.uk



That’s not me in the picture at the top by the way.  Just haven’t figured out how to change the banner yet.  Probably just as well.  Wouldn’t want to put you off your lunch.