Growing fruit tree against a wall?

You could go for a less vigorous root stock. For example using a dwarfing rootstock and growing apple trees as oblique cordons may work - I don't know is the dwarfer rootstocks would be vigorous enough to support an full espalier though.

What is the sub strata under your house?
What are the foundations to the property?

See attached Subsidence Insurance & your Home guidance which suggests 10m away from a house for an Apple tree

Trees and houses on clay are not good and as a structural engineer I would never plant a tree against a house. Roots like to find there way into drainage etc.

That being said I have three apple trees that I have as espaliers against the perimeter wall to my allotment plot on one side - I placed a paving slabs at depth under the tree and I have grown in pots in the ground to ensure restricted root growth.

There again I'm only a Tenant there and I intent to keep them maintained and if I saw any indications of a problem developing in the wall I would have them out in a heartbeat.

Thank you for that! We are on clay and I could double check with ground workers but think it's trench foundations. Is the problem with uptake of the water from clay therefore shrinking it and affecting the foundation, or roots actually growing through the joint between the top of foundation and start of wall?

I just don't understand it as see fruit trees in walled gardens and against cottage walls ☺️

How many people have 10m from house to a point in the garden nowadays ��

If a walled garden cracks, who's worried, if it's the walls to you house that's another matter. It's possible to grow trees as dwarf stock in large pots, its all about risk and the elimination or reduction - grow them in pots you have eliminated the potential for the tree to do harm.

Clay shrinks as the water content is reduced and swells as water content is added. The amount of water obviously varies seasonally and year by year, if you get a dry summer followed by a dry winter and another summer. Then something like tree roots will further reduce the water content in one area more than another and the building starts moving at different speeds and that's when you get cracks appear. If all the building moved up and down as a whole as the clay breaths then there would not be a problem.

In theory the designer of a new build should have looked at what existing trees would have an effect on the building and the depth of foundations established based on NHBC Guidance documents, not a lot of good when someone comes and puts a thirsty tree near to the property and it was not designed for it.

One would also hope that a soil survey was actually done and the properties of the Clay established, this however is not always the case.

I have crawled trough brick culverts where tree roots have made there way into the drainage system to get at the water and the walls and floor of the culvers were completely covered, I have seen clay pipes completely filled with tree roots as roots look for sources of water.

Never underestimate the power of nature and especially trees and the damage they can do.

Thank you. I might grow a potted espalier or a tropical squash up those walls then

The tree-related risk of subsidence is relative to the size of the tree and how quickly it grows.
Big, fast-growing trees tend to use a lot of water while small, slow-growing trees don't use much.

Other risks are the type of soil you have, how much water it holds when it is wet and how much its moisture content changes through the year.
Certain types of property have different quality foundations.

So a big old cherry tree, 40ft tall and 20ft from the house, with its branches nearly reaching the house, would worry me far more than a 7ft apple espalier up against a wall.

Thanks FB!

I had a chat with the ground workers here and they said because of the proximity of the hedgerow (3m away from my garage), the footings are really deep - he said almost One storey (which seems a bit excessive??) so if I were conservative and said 1.5-2m that would still seem like quite substantial wall of concrete. I'll go to office tmrw and see if they might be willing to have a let me look at the foundation dwg.

If this were the case, I think perhaps an espalier would be ok.

the ground drying out is not something we ever have to worry about, just lucky we have really deep black loam that never goes dry and a climate that makes sure that it stays that way, a benefit or a penalty?, after over 15yrs I am still undecided...

We moved to this house in 2014 it was built in 1960 and I had a comprehensive structural survey done before purchase. We have three apple trees and a pear in a row 4ft from the back wall of the house!! The surveyor report ran to 25 pages but nothing was said about the trees, we are not on clay.

Not sure if that's any help, hope you can get alook at the drawings, if the foundations are as you were told it should IMO be OK, but that's just my opinion not an expert