Perhaps if you'd explain what kind of damage the squirrels are doing, someone will be prompt in making some helpful suggestions.

Bostedo, I'm wondering too if they are causing any damage or you are just concerned they might. I have chipmunks that climb a noble fir, run across my cedar shake garden shed roof for easy access to a magnolia...but they cant get in and we do inspect for chewed shakes off and on, aren't hurting anything. So far.

What you are proposing may not meet city code if you are in a residential neighborhood, things that are sharp or potentially injurious on a fence top like the nails, barbed wire, carpet tack strip, electric wire aren't allowed here at least. A low voltage electric wire enclosing a back yard pond (ie raccoons) or berry patch is legal, installed top of a property line residential fence it's not.

It's not in my mothers city either, she had possums running along a privacy fence top, giving them access to climbing onto her wisteria covered arbor over her patio with table. Possums aren't housebroken so you can imagine her dismay at having them overhead.

rhizo_1: It's mainly preventative. Ken is right that our roof has recently become the highway between one of their favorite nesting areas and three or four of their feeding spots. It appears they unanimously agreed on this being the new preferred route after the local tree canopy was altered by removal of a large fruitless mulberry. It's a percentages thing: more squirrels on the roof, then greater risk of problems.

Current problems are trivial as a bit of noise and guard screens damaged or removed when checking for things to eat in the gutters. However, we're down at least $2.5K in damages caused by these critters over the years, so take prevention seriously. Here are some examples of what we are trying to avoid:

• It's harder for them to get into the attic since the original cedar roof was decked for composition. However, they'll still go through any bendable/chewable venting, such as the ridge vents which are just vinyl/plastic under cap shingles.

Then there's the "small (thin) one/big (fat) one" problem with the vent pipes and stacks, especially in the fall when they start chasing each other around. The "big" one gets stuck in the pipe/duct, either trapping the "small" one or forcing it to find another way out... usually into the house. I had thought this unlikely until it happened to close relatives in two different states last year. The in-laws actually had the "small" squirrel come up in their commode - fortunately the lid was down and it had drowned (hypothermia?) by the time they found it. In both cases, plumbers had to remove the bigger ones stuck further up in the vents.
Most squirrels won't mess with wire (or lead), but if one does get fixated on it, there's almost no stopping it. When one starts eating wire, they eat the copper and insulation. On our roof, worst damage would be taking out our comms feeds or lead vent caps.... though if they get inside the attic, potential damage is much greater.
The leaping from the fence to the roof is new. I'm just looking for ideas on how to discourage them from using the 4 to 6 feet of fence top in the four areas that run up to the house where they make their leaps. Backup is to set traps on the roof, but would prefer to avoid this by having them "re-pattern" different routes.

This post was edited by bostedo on Fri, Sep 13, 13 at 10:48

Vic's VapoRub. Tree rats were using the top of my fence as access to my apple tree. A few dabs of VapoRub along the top of the fence as well as some strategically placed on the branches and I was finally able to harvest apples this year. The VapoRub lasts through 2-4 inches worth of rainfall before needing to be re-applied.

The apples,BTW, are 'Honeycrisp' and man are they good!

tj

morz8: Yeah, I'm not crazy about having sharp things on the top of the fence, but was the first practical option that came to mind. Not sure what the local ordinances say, but suspect around here I'd more likely be called out on the technicality of taking the fence above 6 ft without a permit if it even became an issue. Any barrier I try will be temporary and discrete, though am hoping the VapoRub suggestion pans out.

Opossums run our fence to get to the magnolia fruits, but they stay off the roof; have notice they are very "regular" and dread the thought of having them overhead as in your mother's arbor.

tj: Vic's is on the shopping list! Other squirrel repellants we've tried for our peaches, pears, and tomatoes have not been very effective, so am hoping we have similar success. Thanks for the idea - we'll buy it in bulk if it works.

Yesterday I rounded the corner and came face-to-face with a squirrel that was about to make the leap. He was so startled that he nearly fell off the gate..... and I was so startled that I nearly reached out to catch him.

Tried the Vick's VapoRub, but it had absolutely no effect whatsoever.

Single strand electric fence.