How do you build to keep packrats out?

I have heavily wooded undeveloped acreage in the Okanogan Highlands (Northeastern Washington State USA) at about 3500-4000 ft elevation. Anyone who has built a structure in this area has problems with packrat infestations which occur if an active human presence is not maintained for even a day or two. They get into everything, filling structures with feces and gathered debris, and chewing anything including the insulation on electrical wires in vehicles. They dig, chew, and squeeze through small openings. They are amazing critters, but for health reasons I'd rather not share living space with them.

Has anyone had success with a building technique that will keep packrats out?

Ann

yikes! maybe you need some more natural predators! honestly my first thought was to get a jack russel terrier! those dogs will obsessively hunt rodents....you just have to make sure they don't run out of something to do and get bored! the urine from a predator might be discouraging too

Hmm. I think I'll look into Jack Russells after I actually build something out there; they sound very interesting. There are many natural predators in the area already, and I'm using predator urine to keep the deer away from fruit and nut trees I planted. I'm not living there yet, and can only get out to the property about once a month. It's a long-range plan, since I don't want to go into debt to "develop" it.

I just don't want to build a structure that will be easy for rats to get into. I haven't met anyone yet with an existing cabin or shed who has been successful in keeping them out. That means wood structures won't work. I suspect cob, straw bale, or other earthen structures won't work. They'd dig right through it like they do with wood.

Has anyone built with cement? I'm wondering if it could work to build similar to the way ferro-cement boats are constructed. That uses formed rebar, a mesh somewhat like hardware cloth, and hand-applied cement pushed through it.
The result might look nicely organic.

I used to be up on mount spokane.  I don't remember any problems with any kind of rat.  Of course, I had cats and dogs. 

Maybe I was in an area that didn't have packrats to begin with?

I've read several things about using broken glass in building construction to prevent rodent entry.  I didn't think much of it, like Leah I would think 'dog/cat' to deal with such a problem.  However the explanation of how they added pieces of glass to the foundation and under the house now sounds reasonable in light of your situation (building before you occupy full time).

I'll see if I can find any of that info and re-post if I do...

~Jami

do they climb easily? if the lower part of the building was all cinder block and you had good sealing steel doors maybe that would be sufficient. if they climb add slippery metal siding above the cinder block pony wall. 

packrats mice and most small rodents can fit through any hole they can get thier face through. and more disparaging, they can climb right up a vertical 2x4 sanded with 80 grit as if it were a ladder. cinder blocks will only help if there is no access above them, as they will climb right up a corner of the blocks to the plate sill.

ive been spending alot of time in a barn  with packrats, wood rats, feild mice and shrews who all wander in...

I keep everything im worrried about having feces in, whether food or bedding, in a mouse proof chest.

all my food is in cages with 3/16 mesh wire laps. i still find stray terds, but i suspect they are from mice on the cage, not in it, as I havent found any evidence of chewing inside.

the best deterent is cats. I keep them in the barn. I dont let them out. owls and bob cats would have them in short order.

ive still got rodents. but they hid alot more now.

the secret to keeping rodents out is to buildyour house from a clear plan with good skills in a short period so they cant circumvent your efforts. by building paths through your work while your building it. then dont leave things that attract them where they can be smelled. and I suspect that mice can smell foodstuff quite well when its within a few yards.

use pennyroyal oil and other harsh mint oils where you suspect they travel- it stings thier feet.

good luck!

Cats aren't a very good deterrent when it comes to pack rats, which are pretty good-sized.  I think the Jack Russel terrier, or actually any of the working terriers, would be a better rat-killer.

Kathleen

That hasn't been my experience; in fact my 9 week old kittens (now 12, and several presents later) brought me this gift as thier firt 'proof of felinity'
...not for the squeamish, 

http://www.facebook.com/photo.php?pid=2869899&l=f89c9c11eb&id=542063253&subject=Album Album

what bothers me is that I havent been able to get a positive ID. Its not a 'packrat' in the typically colloquial, though it does have a very bushy tail. what we call packrats here,  Neotoma cinerea, typically doesnt weigh more than 1/2# as an adult, and is far more coulorful- quite pretty, actually, with red and white accents to a banded body, and the particularly delightful tuft at the end of the tail. and they are amazing leapers.

this is over 2x the size of  Neotoma cinerea; it weighted 1.2 lbs. Im still trying to key it out. it is a neotoma, but there are over 20 species and I dont have a guide, so am parsing it through internet searches... regardless, the cats are working great

Before we moved to Klamath Falls, my grandmother lived on a property with two houses, one of which was empty for about three years before we moved over here.  In spite of the fact that she had three cats who spent a lot of time in the empty house, it was totally taken over by packrats.  Grandma, who had spent ten years dealing with and caring for my grandfather in his final illness, and who was ninety, hadn't been able to do anything to deal with the rat infestation, and when I went in the old house to gather up some things to bring with us here, the floor was covered with rat pellets.  So was everything else.  There were a lot of things stored in the old house that simply weren't salvageable, unfortunately including a bunch of books I would have liked to save.  The cats did nothing to deter the rats.  That's why I think a dog would be a better choice.  But if you have kittens who are already dealing with rats, then go for it!  Thankfully, we don't have to worry about them in the house we are in right now, although I've had trouble with mice in the goat shelter (the cats did their job there, finally, although I think the chickens had something to do with it as I've seen them eat whole mice!).

Kathleen

Owls, buy several owls 

I know a lot of homesteaders get abandoned chest freezers and keep lots of stuff in those - to keep the vermin out.

I have an ermine that lives under my cabin - no pack rats while he's around. 

Lots of lessons here:  http://en.wikipedia.org/wiki/Corn_crib

My parents live in the Ozarks (central Missouri) they have a Jack Russel and she relay get after the rats for sure.

Straw bale house on a frost protected shallow foundation concrete slab, stucco inside and out.

Hmmmm ...  are all terriers "rat terriers"?

Packrats suck.
It's not very nice but I use a five gallon bucket 1/2 full of water with a baited counter balanced board on the top coverd with peanut butter The rat climbs on top the board flips over and the rat drowns in the water.
Cought 7 in 2 days once.

In our forum discussions we are pretty well set on 1/4 inch hardware cloth being about the only thing that will keep rats and mice out of a building including covering the entire underside of the floor to keep them out of the insulation.

Perhaps you could use a shipping container?  There are tons of those in the Seattle area, they can be converted to quite nice housing, and can be sealed up using the original doors on the end when you leave.  You'd probably build a wall with a window/regular door inside and leave the large doors open until you need to shut the place down.  Good luck