Is it possible to over insulate a loft?

[Wingedharpy]

Fairly recent cracks appeared at ceiling height, where ceiling meets party wall.
Victorian terraced house.
Crack runs along length of wall and has started running down towards floor level (but doesn't stretch that far).
Only relatively recent activity in this room was the installation of insulation in small loft above the ceiling (single storey bit of house).
I did the insulating and just flung new, thick insulation over the top of the old stuff - it was dry.
I admit to just chucking it about with gay abandon rather than following any specific method.
Could my DIY efforts have caused the cracks?

Yes it can be too heavy or it can impede air circulation and cause condensation and mould.

Don't be daft, the insulation won't be too heavy, there will be another reason for the cracks.

More likely to have been you stomping around putting the insulation in. Adult much heavier than insulation board.

Have you had any plastering done there? Or extra work? Cracking can be from settlement, we've had a loft conversion and extension and that caused cracks - whole house was replastered

Loft insulation does need some care though as it can lead to condensation if airflow isn't right - personally I'd get a few people in to give some info - we had 3-4 people give us opinion on our cracks all said they're settlement

Are you on clay soil? We had this when we lived in a Victorian terrace after a drought period and we were told it was seasonal movement.

Over insulation would mainly result in damp / condensation issues - ie not enough ventilation etc. You’d probably see this as black mould or even water collecting around light fittings (this happened to us). The cracks are more likely to do with usual movement of the property or the fact you went up into the loft area - pressure etc.!

Too much insulation does cause issues but it doesn't cause cracks.

My ndn is into model railways, they've lived in their house for nearly 30 years and he'd insulated ed the roof so his trains can go there. They've just had to replace all the felt and timbers in the roof due to them doing this, it's caused the timbers to rot away due to moisture being trapped as the insulation wasn't able to breath

No stomping took place during the course of my efforts to warm up the house.
No clay soil here - very sandy and light.
No new plastering or any other work of that nature done recently.
Loft seems very dry - and like an oven when I went up there yesterday to check, though, it's difficult to see far due to amount of insulation in there!
I'm going to have to remove all this bloody stuff aren't I?

Move it away from around the edges where the air should come in to ventilate, it doesn't address the cracks though, that is a puzzle.

Monitor it for a while, it could be coincidence or you maybe haven't noticed it before.

the insulation is not the cause of the cracks.

Post some photos please.

@harknesswitch

My ndn is into model railways, they've lived in their house for nearly 30 years and he'd insulated ed the roof so his trains can go there. They've just had to replace all the felt and timbers in the roof due to them doing this, it's caused the timbers to rot away due to moisture being trapped as the insulation wasn't able to breath

do you mean "sprayed foam" insulation?

Will post pics tomorrow when light available.
I'm truly grateful for all comments and opinions.
I don't feel ventilation is an issue as, due to the quirky nature of this old house, our party wall, where the crack started, doesn't go all the way to the roof. It is possibly 3 foot high once in the loft so, in reality, I could step over it very easily and be in my neighbour's loft.
I haven't asked him about cracks on his side but I don't think he would be able to see them even if he has them.
It is his kitchen and I suspect the wall in question will have wall cupboards all along it.

Pics

As requested.
2 inside loft and 3rd showing crack below hatch.
The wall in question, extends just 2 feet above the hatch.
Neighbour's loft is on other side.
I'm thinking maybe structural engineer's view is the route I should be going down but would appreciate anyone's input.
Thanks.

I don't know what it is. It's mostly a vertical crack, and in the exposed loft brickwork it seems that both the joints and some of the bricks have cracked, and seem to be opening up. I think I can see the original lime mortar, but possibly also a previous cement repair. Has there been structural alteration, such as removing a wall to "knock through" two rooms? Or removal of a chimney breast? In either of the houses?

Has there been a long-term water leak?

Has anybody made loft alterations, especially cutting out some of the original timbers? Or removing original lightweight roofing slates and fitting new heavy concrete tiles? Or putting heavy items in the loft?

How long ago was the loft hatch hole cut, or enlarged?

P.s.

It is definitely not caused by insulation.

With it being Victorian the house will be built straight on the clay ( no concrete). It’s been an extremely dry period for the time of year and it could be the clay drying out and the house moving slightly??? As the house has been there over a hundred years and is still standing I don’t think it’s going anywhere.

You get a lot of this with old houses built on certain types of ground.

M not an expert and it’s just a suggestion of what it could be 🙂

We've lived here over 30 years so no knocking about of anything in this room, or adjoining room, in that time.
Originally, this room started off life as a lean to/coal hole type of structure and was extended, way before our arrival, to form a larger garden room.
Where the original meets the new though, is probably 3 feet away from where the crack is.
Loft hatch was here on our arrival and the original roof tiles are still in place.
All the woodwork(?trusses) appears to be dry and in good condition, as far as I can tell.
There are no water pipes along this side of the house but there is a sink and washing machine diagonally opposite. No signs of any leakage from either.
We're fortunate enough to have plenty room for storage in our house so there is absolutely nothing stored in this loft - other than an excess of insulation!
Neighbour states he has no water dependent appliances or water pipes along this party wall either.
@Chumleymouse, ironically, this bit of the house is the only bit of the whole place that has a concrete floor and foundations.

2 things which may, or may not, be relevant.

Approx 11 years ago, neighbour had his house underpinned.
No party wall agreement etc (don't ask).
Could it be that both houses were gently creaking along in unison but now that he's fixed rigid, we're still gently creaking but he's not coming with us, so this is adding strain and stress on our structure?

2nd thing, possibly 8 years ago, we had some decorative wood panelling and dado rail feature, put on this wall.
Could the difference in the way wood, plaster and brick reacts to temperature and humidity have caused this?

It could well be his house is not moving much anymore and yours is slightly due to changing ground conditions ?

Fill in the crack with a bit of filler , then keep and eye on it to see if it opens up anymore.

If your houses are joined, and one of them needed underpinning, I would have thought the other did, too.

I can see why you'd say that @PigletJohn, but, his decision to underpin came after chatting to a builder who was working on a very neglected property further down the street.
The builder informed him how shallow the foundations are on this type of property - I thought this was fairly common knowledge but apparently it came as a surprise to my neighbour.
Builder was underpinning neglected property, so my neighbour decided to do the same.

I'll get a structural engineer to have a look and see what s/he says.

If the worst comes to the worst and we do have to go down that route, anyone have any experience or views on Geopolymer injection for underpinning?
It appears to be less invasive than digging ruddy great holes in the floor of our home😥😥