Step by step guide on how to build a rodent proof sub area access door.


The old door, in Picture 1, was installed by a licensed, experienced contractor.  He was not however, experienced at rodent proofing.  this door had a half inch gap at the bottom so that it would close over the irregular concrete footing.  It had a half inch gap at the top to that it could fit under the slightly sloping siding above it.  You can't tell by looking, but the door had also warped, which left a half inch gap where the non-hinged side closed against the foundation.  A mouse only needs a quarter inch gap.  A rat can easily squeeze through a half inch gap.  This door was installed to keep rodents out, but did not meet that goal for even one minute.

Picture 1.



The first step was to remove the existing door and any framing that would interfere with the new door.  I took everything down to the bare concrete as seen in Picture 2.

Picture 2



Next in Picture 3, I installed a 2 X 4 base for the frame.  I always install a frame for the door to set into, patterened, at least somewhat, after the frame that any regular door would set into.  This base would corespond to a threshold.  the frame is glued in place using all weather subfloor glue.  The glue is applied everywhere the wood touches the concrete and as a caulk to fill any small gaps.  All the wood used in this project was pressure treated, ground contact rated wood.

Picture 3



Next in Picture 4, I installed 2 X 4 sides that fit from the base, or threshold, up to the existing siding.  These pieces would corespond to the very exterior part of your average door frame, the casing.  This is one specific way of installing a door.  There is another type where the frame is built inside the concrete opening into the sub area.  This opening was so small though, that to save access room, I modified our normal work-up.  Again I use the subfloor as both a glue and a caulk.

Picture 4



Above the two newly installed sides, I installed a 2 X 2 nailer.  I used deck screws to anchor it back into the siding and the structural wood behind it, and I used the same type of screws to anchor the 2 X 2 nailer down into the 2 X 4 side pieces of the frame running up from the threshold to the siding..

Picture 5



In Picture 6, you can see that I installed two pieces of 2 X 2 running from the 2 X 2 nailer at the top of the opening back down to the base, or threshold.  These 2 X 2 pieces were screwed into the 2 X 4 side pieces behind them.  The need for these will become apparent in the next frame.  If you look at a regular door frame in your average house, you will see an inch and half by half inch strip of wood that is set in the middle of the frame that the door closes against.  If you look closely at Picture 6, you will see that a slightly larger expanse of wood now exists that a door could close up against.

Picture 6



I then installed a piece of 2 X 2 that spanned the top opening, just below the nailer.  This was attached with wood screws up into the previously existing framing of the home and also into the two 2 X 4 side pieces I installed in Picture 4.  This gives the entire opening an inner frame.

Picture 7



I cut the 2 X 2 wood in Picture 9 to build a frame for a door that would fit inside the inner frame.  I made the door about a half inch narrower and a half inch shorter than the maximum size of the inner opening.  This makes the door easy to get in and out, but still allows the door to fit flush up against the inner frame. 

Picture 8



I used 2 X 2 corner framing hardware to attach the pieces of the frame together.  I used one inch lath screws to attach the metal hardware to the 2 x 2 treated wood.

Picture 9



Prior to screening the 2 X 2 frame, I made sure the frame would fit properly into the opening.  There is nothing more frustrating than making your door too big and having to take it apart and rebuild it.  As you can see in Picture 10, it fits just fine.

Picture 10



Next I applied quarter inch hardware cloth to the opposite side of the 2 X 2 door frame than I attached the metal hardware to.  This will allow for ventilation and it will keep rodents out.  It also makes the door light and easy to pull out and replace.  The screen is attached with staples every few inches.  Be careful to make sure the screen stops at least a half inch before the wood does as this makes the door easier to handle.

Picture 11



In the final picture I placed the new door into the opening.  To secure it in place, I used two deck screws in the middle of the frame.  One on the top and one on the bottom.  It is hard to tell from this picture, but the screen is facing inward.
Picture 12



Picture 13 illustrates the slight gap around the door which allows the door to be removed and replaced easily.  If a door is too tight, it is too easy for service people to not close it properly.  Remember, the opening has an inner frame that the door is actually attached to with deck screws as detailed in picture 12.  You and any service people you hire will need a electric screw driver or drill to get access underneath, but really, how often does the average homeowner crawl under their home?

Picture 13

If you would like full size, high resolution pictures, simply drop me a comment with your email address in it.