Author Topic: Square Pipe 4"wide by 3.25 deep  (Read 6016 times)


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Square Pipe 4"wide by 3.25 deep
« on: March 08, 2013, 06:54:35 PM »
My dryer is not venting well.  I discovered if I pulled it away from the wall and "unkinked" the hose it worked fine.  So I am looking into the dryerbox as a solution.

I cut the drywall to look at what I had.  There is a rectangular 4x3.25 pipe going up through the ceiling and into the attic.  There is a 4" diameter pipe the juts out of this rectangular pipe at a 90 degree angle.  This is the pipe I attach the dryer venting hose to. 

How can I convert this system to something like the dryer vent box where the hose connects in-line with the pipe?  Or is it even a worthwhile to attempt it.


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Re: Square Pipe 4"wide by 3.25 deep
« Reply #1 on: March 11, 2013, 08:38:20 AM »
Great Question and we do appreciate you asking it here in the forum. 
In the past, it was common to hear of gutter downspout pipe being used in a 2x4 wall, to vent the dryer.  But now a days we do not hear that much.  Also, it was common to find a 3x10 rectangle pipe with the same connection of round to rectangle that you explained.  Both of these are very inefficient and usually leave a "pocket" for the lint to fall down into at the bottom. 

If one of the reasons for going through a retro install of a dryerbox is to move both appliances back maybe 5 inches, or to make the dryer run more efficiently, or both, then it is worth the effort if some of the conditions are right. 

The scenario number 10 of 16 at the bottom of this page: is of a 2x4 wall that had no vent pipe, but had 4-6 feet of working room height in the attic just above so we were able to first confirm there were no obstructions, then cut the top plate out, and send 5 foot sections of round pipe down the wall.  Yes, 4 inch pipe fits and works, it’s just deformed a bit to oval.  The person at the bottom reached up through the dryerbox and steered the hard pipe into the dryerbox port.  It was amazingly quite easy with two of us and room in the attic.  We then installed a DryerJack (roof vent) and the homeowners were very happy. 

Make sure you look at that link above, and any other similar retro installs on that page.  I'd also very much like to get your before, during and after pictures of the install if you elect to tackle it.  I will be happy to discuss this further on the phone if you have more concerns.  Thanks and good luck. 
« Last Edit: September 22, 2014, 02:17:54 PM by rickharp »
Rick Harpenau
In-O-Vate Technologies, Inc
Jupiter, FL  33477


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Re: Square Pipe 4"wide by 3.25 deep
« Reply #2 on: April 10, 2017, 06:24:14 PM »
Keith, did you ever come up with a solution for your install?  I am in the same boat with 3x4 inch ducts in my wall.   It looks to be strapped to the studs, so removal seems difficult.   I am going to check on the price of getting a custom round to square transition built at a local duct shop.  In the attic, strangely enough, it transitions at the top plate to 4" round pipe.