Tree planting for new build privacy

You could spend 50 euro (very small bear root trees) or 10k (mature trees) pick something you like the look of, check it doesn't grow two bitlf (unless your happy to prune even year or so) honestly there is a huge choice and price available. Are you looking for evergreen?

We need a lot more specific information before offering any useful suggestions. 70sq m in its simplest formation could be a square garden 7m x10m, or it could be an sort of shape possibly going to very narrow bits down the side of the house. Draw a rough diagram showing the shape of the garden, placement of the house and an indication of measurements, also which direction is north, and where the block wall is, then it might be possible to give some helpful suggestions.

Seems this is a job for Nellie R Stevens

Dark ever green Holly, call Nellie Stevens , shape any way, and any height. Privacy all year round, and they never grow big thick branches, easy to trim

Just don't plant leylandii trees whatever you do .

That's a very small area. You can't plant trees to block 3 sides. Consider the impact on sunlight for your own and all the other gardens by raising any kind of 3mt barrier.

I would suggest planting a few hornbeam at the sides and back, just where you want to block a view.

Sit in the sunny spot where you want to sit out in privacy. Look where the windiws overlooking are and this is where you need to position a tree.

You don't need a full block out as this will impact on your space and light in the garden.

Hornbeam are light with small leaved branches that can be moulded around a shape or pergola, wired /pleached along a wall or fence and won't block out all the light.

https://images.app.goo.gl/qRdDj3QPt1Hgws8k8

Not evergreen but most people don't mind in winter as not sitting out as much.

I would recommend keeping anything big you put in cut back at least once a year or they will just become unmanageable.

Anything near the house it is especially important not to let get overgrown as the roots may damage foundations and block light from your windows.

Another nice one is birch.

+1 for the hornbeam, they are a narrow form tree in a ‘lollipop’ shape with no low branches and can be pruned to only branch out at the height of your wall, providing screening where needed. They can also be pleached to provide a hedge on stilts, and can be complimented by planting lower height shrubs between. Consider the Carpinus Betulus Lucas or Frans Fontaine

My 2 cents worth. Have you bought the wrong house.? You cannot get privacy in a layout like that without growing massive hedges. That will kill your light and also you neighbours. The neighbours will grow to dislike you in proportion to the tree height:-)

Can you pull out of the sale and buy a house with actual privacy?

Bamboo is an awful weed that self seeds and will take over your garden and neighbours garden in time. It should be illegal to plant

Also, think how you would feel if all your neighbours planted big high hedges and blocked your gardens light, meaning you have no sunlight anywhere.

You have a house in an estate. You need to have mutual respect with your neighbours.

Just be careful with privacy screens. They get scruffy looking unless they get painted every other year or so. If you grow something like clemitis roses jasmin it becomes impossible to paint.