Smell from neighbours

[LovesAutumnColours]

My house is less than 10 years old. My neighbours kitchen is the other side of the party wall. Every time they use their electric oven a foul smell pervades my whole house. There must be a ventilation problem somewhere.
Household name building company that constructed the house, the NHBCC and buildings insurer all refuse to investigate the problem.
Who should I employ to investigate? I know there is a problem somewhere.
Local council have suggested I log incidents (easy it's almost every day) and say they will investigate smell as a form of nuisance pollution but I am good friends with my neighbour and don't want to start a war. Please help

@AlmostCutMyHairToday Useful advice. Thank you

Oh yes, I get the smell you mean 😒

I've had similar in a holiday rental once and never found what it was despite a lot of cleaning (not even my flat)!

I did wonder about mice or rats, but hopefully not

I would ask them to get their oven checked? I had a similar issue once, albeit it was in my house I could smell it, and it turned out the oven had been installed wrong and was slowly burning through the wires each time it was turned on.
Or could it be an oven hood extractor fan problem? Maybe it's vented incorrectly and the smells are coming into your property?

Slightly sweet compost is the smell of dry rot.

Leak from upstairs to the back of their cooker and under the floor in the adjoining wall?

Does their kitchen back onto your house?

@NerdWhoEatsMedlar Our ovens are exactly either side of the party wall (hope you get what I mean)

Smell pervades the whole house

@Crojo re the cooker hood I wondered the same thing.
Builder and NHBC refuse to investigate

@LovesAutumnColours are your bathrooms above the kitchen?

I wonder if they have a cooker hood, and instead of extracting outside, it is venting into the wall or ceiling.

@NerdWhoEatsMedlar No both houses have a bedroom above kitchen

@HairyPie I don't think the neighbours are doing anything deliberately.
I think something went wrong somewhere when the house was being built, that something wasn't done or finished properly

@PigletJohn I'm guessing the cooker hood recirculates air. We both have stainless steel chimneys. Are they just for show or do they vent anywhere? There are air holes in my stainless steel chimney where it touches the ceiling, they are stained! No idea why or how

@HairyPie It's been happening almost every day since I lived here!
At first I would come home from work and think it was my kitchen bin.
Eventually I realised it wasn't my bin or anything in my house and that it coincides with times of the day when they are using their hob/oven

Has next door neighbour been into your house when the smell is there - have you invited her round when it happens to see if she can identify it?

@HairyPie Yes both houses have a downstairs loo next to the kitchen

@HairyPie I was disappointed by the attitude of both the builder and the NHBC neither of who would accept what I said or were prepared to inspect inside the loft.

I think there is something wrong with how the houses were built. Somehow.

You hear loads of nightmare stories about new builds

I suppose you could ask her to rub something scented on the cooker hood, and see if you smell it in your house.

I think it's probably time to have an honest and kind chat about it.

"I'm sorry to be awkward but I notice a strange smell everyday when you're cooking that fills my house. It's definitely not your food, it smells like something's wrong with an appliance or ventilation perhaps. Have you smelt it? I hate to be awkward but would you mind if I paid for someone to take a quick look?

If a neighbour said anything similar to me, I would be embarrassed but very keen to get it sorted for them.

Sometimes honesty is the best policy and you won't know until someone checks it out.