Drilling vent holes - scary stuff!!! - Fiberglass RV

Thread Tools Search this Thread Display Modes
Old 09-05-2013, 11:06 PM   #1
Junior Member
tabmbb's Avatar
Name: Tom
Trailer: 32' 2007 Keystone Cougar TT
New Hampshire
Posts: 1
Unhappy Drilling vent holes - scary stuff!!!

I need to drill two 4" vent holes in the sidewall of my 2007 Keystone Cougar. I have bought a 4" hole saw for this purpose but I am stuck at this point. How can I determine proper placement of these holes so that I don't cut through any studs, thus weakening the units integrity? Is the 4" hole saw the way to go, or is there a better approach? Do I cut from the outside in? How do I determine and avoid stud locations? Will a standard carpentry type stud finder work on fiberglass? I would greatly appreciate any thoughts or suggestions on this problem.

This project is to install a portable A/C in the bedroom. The unit on the roof works great until the temps hit the 90's, and then the bedroom becomes like a suana. The vent holes are to install intake and exhaust vents. Also, any thought on how far apart these vents should be to avoid sucking warm exhaust back into the intake vent? I had considered a second roof unit but decided that my roof would not support it.

tabmbb is offline   Reply With Quote
Old 09-06-2013, 05:51 AM   #2
Senior Member
Name: bob
Trailer: 1984 u-haul ct13; 1996 Casita 17 Spirit Deluxe; 1946 Modernistic teardrop
New York
Posts: 4,549
Try a stud finder. Also consider the possibility of any wiring in the wall. Can you make a small opening on the interior wall to see what's in there first, then cover it with some kind of trim piece if necessary.

mary and bob is online now   Reply With Quote
Old 09-06-2013, 06:53 AM   #3
Senior Member
Bob Miller's Avatar
Name: Bob
Trailer: 1973 Hunter Compact II
Posts: 7,912
As they "might" have said in The Treasure of the Sierra Madre; "Studs, we ain't got no stinkin' studs".

About 99% of the trailer owners on this site have molded fiberglass trailers, all built without studs, and none big enough to have to worry about needing a second a/c for the bedroom (LOL)

The technique I have used is to cut a 1" hole in the area I wanted to explore and then use that to look around inside. If it proved to not work out I could always stick a small 4" diameter vent cover over my boo-boo.

You might get better information and help on a site for your make trailer and/or on sites for what we refer to as "stick-built" trailers.

That said, I once tried to use a stud finder and it just kept pointing at moi! (LOL)
Bob Miller is offline   Reply With Quote
Old 09-06-2013, 07:30 AM   #4
Senior Member
Name: Steve
Trailer: Casita 17 ft DLX SD
NW Wisconsin
Posts: 3,080
Drill a small hole in the location you desire the 4" hole . Stick a small piece of stiff wire bent in the middle through the small hole and try to rotate the wire in the hole , If there is something in the way the wire will hit it. It is a lot easier to patch a 1/4" screw hole than a 4" screw up .
steve dunham is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Solar Panel Installation - no drilling holes carlkeigley Modifications, Alterations and Updates 39 09-13-2013 03:42 PM
Tips for Drilling Holes in Fiberglass Lil M. Modifications, Alterations and Updates 33 08-17-2012 05:46 AM
Putting drain/vent holes on Bigfoot trailer? Bluebamboo Problem Solving | Owners Helping Owners 0 06-21-2012 02:48 PM
Scary Tire Report on 20/20 Last Night Joe Z General Chat 2 05-10-2008 08:49 AM

» Upcoming Events
No events scheduled in
the next 465 days.
» Featured Campgrounds

Reviews provided by

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 09:14 PM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.