Rear house wall disaster?

[GreenDragone]

We started a major 10 month extension to our house & when work was well underway, our dc developed a life-threatening condition which meant they spent a year in intensive care - having multiple surgeries & nearly dying many times along the way. To say I was strung-out is a major understatement. The build had to continue because we had no back or side wall at all across both the ground & 1st floors of our home. My dh & I basically left the builders to it most of the time, just checking-in briefly once or twice a day. During the build I noticed that the rear wall footings (I mean the first few rows of bricks on top of the foundation) had no gap between them - unlike the side wall of the house. The builder pointed to the architects plans which showed a 'thick solid line' where the rear wall was to be - different from the kind of line drawn for the side of the house. The rear wall is not load-bearing at all - see pic. The architect had gone off on holiday. The problem is, the builder offered to change the construction of the rear wall to a regular 'double skin' & I didn't know what to say for the best. This came at a critical moment for our dc & I just said 'leave it' & dashed back to hospital. So, long story short, we now have a finished extension, but the rear wall is solid (two bricks thick) with the insulating foam on the outside of the building which is rendered over with pebbledash. I'm having kittens over this now we've had time to settle. You can't fix anything to the exterior like lights without having to have super long screws to screw through the pebbledash & insulation. I'm not sure what the story is with the airbricks either.. It's giving me kittens that when we eventually come to sell a buyer will kick up a stink.. The construction was inspected all along the way by the council & we have all the certificates for building regs & planning etc. The weight of the original back wall of the house is held up by a steel box frame, so the new rear wall isn't load-bearing.

It's taken us a long time to be able to look back at our build as we were SO strung out & exhausted when our child finally came home. I dropped to 7 stone myself with all the stress. Please tell me what you think. I'm wondering if we need to have the rear wall taken down & rebuilt? But the interior is finished now so how would that work? & It'd cost a fortune.. There is a window & a set of bi-folds in this rear wall. Help! Pic is of a side view

My husband is a builder and says if it has all been signed off by building control, it should be fine.

I am a building control surveyor.

Walls can be solid as opposed to cavity and they can be insulated on the outside.

Can you think of any reason why either the architect or the builder would have thought this construction a good idea? My neighbour who has done the same extension since I did mine, has a traditional construction rear wall. The trouble with pebbledash over foam is that it's not strong - as I found out when I jet-washed the decking & accidentally knocked some off...

Husband said it is quicker and cheaper than a double brick wall with insulation in between.

Yes, exactly. Quick and cheap.

they might have designed it to be built in solid lightweight blocks as it is not load-bearing. I don't know that it would work out any cheaper if you then had external insulation added. The architect should have annotated the drawings or added a detail sketch.

I have one wall somewhat like that, most of it is slate-hung, but the first two metres from the ground are clad in shiplap which is more durable and withstands people bumping into it.
I've seen it done in Switzerland where they render onto cement boards over the insulation.

The construction method is ok, relax and enjoy the house after all you've been through.

Speak to the builder about the piece of render falling off though, they should make that right at their own cost.

Yes that will be fine, ours is like that on the drawings although the builder messed it up T the bottom and did a thicker one. It's to do with preventing thermal bridging and condensation, as the steel beam is solid rather than cavity if you see what i mean, so the rest of the wall follows suit.
To be honest you shouldn't really be pressure washing your house, there are lots of details that are only design to handle falling rain, or splashing rain in the case of the lower wall.