I think 'non-permanent' is going to be the keyword here. Anything not planted permanently around here is not subject to bylaws, permits or zoning. Would a series of narrow planters w/verticals & wires supporting a deciduous living fence do the trick? It could be taken down w/containers put in storage at the end of fall and planted again early each spring...

Thank you susan I thought about that but wondered if the city would see it as some kind of smart arsed spin on the rules.

Trellis are not fences, and vines are not shrubbery. I've created a tremendous amount of vertical interest with that technique. It's a loophole, I know but it isn't a fence, and it isn't a shrub. What about evergreen fastigiate trees?

In many townships here we have the same by law.

This is put into effect for several reasons.

1- safety .- a car or pedestrian often times cannot see around the corner of a high hedge , thus visualizing an oncoming potential accident. The 3 foot heigh limitation is suppose to provide the open air space for unobstructed viewing.

2.- aestethics for sense of community. - tall front facing hedges, walls and fences, contribute to the making of a walled out society.
I don't personally agree with this law because not all spaces are 'black and white'. There are times when a tall front yard hedge is better for the community and homeowner but because of either laziness or lack of funds the lawmakers created a black and white law with no room for grey.

You have a couple of strategies that you can play.
One is the temporary card, as Susan had mentioned. Another option is to install roller blind at the deck.
More and more people are doing this in areas that have this 3 foot height rule and some of the roller blinds and shoji like screens are becoming quite creative.

Law makers have no imagination and often times see things only in black in white.
It is the designers of the world who see a good grey when the opportunity presents itself.

Put a grey spin on it Tony and put a knot in the politicians knickers.

I agree with the impermanence of the trellis/vine. It's not a fence. It's not a hedge. The purpose of trellis is to support nice climbing plants, which themselves don't comprise hedges.

Trellis can be used in sections - for example, an "L" shaped corner trellis of two pieces hinged together like a floor screen. You can even use 2- or 3-panel Asian-style folding screens with woven bamboo, reed or wicker, strategically placed to conceal a dining area.

Before we ripped off our decrepit back porch, I was looking for a way to keep the setting sun bearable as we ate there. A quick section of el cheapo trellis and some canary vines made a rapid and beautiful screen. The thing with vines is if you live in a temperate zone, one can plant either annuals or deciduous vines and accomplish the result they want, and that is privacy and sun screens in summer and with the loss of leaves in winter admittance of sunshine. One seldom sits at their outside table in Canada mid winter anyway.

Can you sink the patio?

Yeah--I haven't designed any sunken patios, but one of my favorite places at an aunt's house was a sunken patio in the middle of her big backyard. It was dug into the lawn, about 2 steps down and surrounded by low plantings. In retrospect, it's surprising how special and secluded that small patio felt, not like being in the center of a big lawn at all, but like being in a separate room, defined by the "floor" instead of the "walls."

With sidewalks on 2 sides, is noise an issue? A low-key water feature (white noise of running water) helps a lot, both to minimize noise from outside and to keep private conversations private.

Is there a setback? If it's 3-5 feet, maybe you could do a wall or taller screen on only one side (whichever faces the busiest street) and then use one of the other ideas for the other, assuming you could still make the space feel like a room this way.

Try doing a mockup with table and chairs, and see what height you need to make the space feel private. Maybe some small trees or shrubs in pots would work, or some grasses that technically are only a couple feet tall, but 4-6 feet in bloom.

How about building an arbor next to the house, set up so that you could hang some sort of "curtain" (greenery or fabric) to screen the dining area from the street? I'm thinking an oasis vibe, tents in the desert, mosquito netting, or just something like curtains of scarlet runner beans on the street side.

I am still not sure how this cookie will crumble but thank you one and all for the suggestions it has been really helpful.

This by law seems like BS to me. As someone who used to work at a local planning office call the local councillor for the area and apply for a variance which is a small legal exception for the by law. The local planning office may have a form to apply for it. If that doesn't work call the councillor and get that by law changed. 90cm high? People are entitled to some privacy. Since when did anyone tell people in the states how they can use their land? The queen owns everything up here, we're just leasing!

The way this story unfolded was quite interesting: obviously things like this only meet the attention of those in the Town Hall when someone complains. My client was in a whirling frenzy about what to do and eventually cut through some beaurocratic nonsense and actually spoke to someone in person ( a feat in itself).During the course of the discussion the Town Hall guy suddenly asked "What did you say your address was?" A bit taken aback he said "4001 *******", the b'crat then said "We have a complaint before us regarding a fence at 4005 *****" . Somewhere en route the address had been wrongly transcribed so Officially there had been no complaint about my clients property. What do you think of that? The patio is in, the fence is still up and we await further developments.