Cracks appearing all over the house, movement in the floor - can someone recommend a structural engineer? ;-)

[AndyZ]

Hi all
I've been browsing this forum on and off for a couple of years - since I bought my current house.
I bought an old (circa 1780) cottage over 2 years ago. It was a small cottage with an extension added most likely shortly after it was built and a long single story extension at the back, which was originally used to keep chickens and was converted into a living space over time (in 1986). The house has its fair share of various issues and shoddy DIY but recently I got slightly worried as over the last few weeks a lot of cracks appeared on internal surfaces. They are anything from hairline to about 1mm wide and follow straight lines between walls and ceiling, walls and floors, around windows and doors, between panels on the ceiling etc. After browsing this forum I'm 99% convinced this is due to changes in temperature and humidity. In the spring we installed a new boiler, replaced some of the radiators and fitted a woodburner in a previously completely open fireplace, so the house is now a bit warmer and there is less humidity (the meter that used to show humidity almost constantly above 70% now shows 60-65%).
What worries me a bit is the fact that a lot of those cracks appeared over a relatively short period of time (around 4-6 weeks) and new ones keep appearing.

The other thing is that the house is built on a very slight slope and the floors on the ground floor became more uneven (they were uneven to some degree before) so I'm worried a bit about movement. This is especially true in the single story extension.
When I bought the house, the structural survey said that there are signs of movement but they are typical for such an old property and appear to be historical. The house had diagonal cracks visible on the external walls, which were filled in and painted last year... these cracks gradually reappeared over the next few months but are no bigger than before. No new cracks appeared on the external walls.

Does any of this sound like a potential bigger structural issue? Can anyone recommend a structural engineer specialised in old properties bases in Cambs/Suffolk/Norfolk (I live in Lakenheath, between Newmarket and Thetford)?

Many thanks!
Andy

 

[Kearn]

My guess is you've got gypsum plaster / concrete render directly onto brick or stone. Which will always be too rigid for an old house. Historic movement may be significant, but an old house is always going to have a little wiggle.

I can't quite square in my head why the accelerated incidence of cracks is related to the temp change.

We've got an early Georgian brick extension, which an idiot has concrete rendered straight onto the brick after removing the original lime plaster. This room shows more and more cracks each year. Always relatively straight too, horizontally or vertically. Depending on size of the cracks, a flexible filler may help hide them. Although others will surely appear. The only 'proper' fix is to remove the offending modern coverings and reppace with a more forgiving lime which can absorb the movement. Or just continually patch and repair the cracks aesthetically if the impermeable covering isn't doing any moisture retention damage as in our scenario.

However, of your floor is genuinely showing signs of movement, you may have a much more significant challenge.

What are the materials we are dealing with here - floors / walls?

 

[AndyZ]

Thanks!
Re temperature/humidity - various materials contract/expand at different rate when temperature and/or humidity changes so I thought that as the house interior is now less humid and warmer, as the temperature drops outside it can result in cracks... I may be wrong though...

Regarding the materials - you're absolutely right - there's a lot of modern materials used throughout - cement render on the outside and gypsum plaster on the inside. The original walls are made from flint and chalk (I think) blocks. Unfortunately the previous owners weren't bothered about using original/correct materials.
Floors are mainly wooden laminate on god knows what... probably concrete but I'm not sure. The floor was always a bit uneven but it just became more noticeable recently. This mainly impact the extension at the back, which used to be used to keep chickens so I have a feeling that there was never proper floor installed there :/ The walls in this part of the house are mainly flint patched up with bricks in some places.

 

[MikeG]

........ The original walls are made from flint and chalk (I think) blocks. .......

This is the key information. I wonder if what you think is chalk is in fact "clunch" (which is chalky, but cut soft, and dries out to solid over the years). If it is, then to plaster that with modern materials is asking for trouble. Further, adding heat into a building which has been irregularly heated previously is also likely to lead to minor cracking issues.

I would recommend Nick Harcourt-Powell (Sudbury, Suffolk), who is highly experienced in this sort of issue in East Anglian properties. He may not be prepared to travel to Lakenheath (I don't know), but if not he should be able to put you in touch with someone who can help.

 

[AndyZ]

Thank you Mike! Yes, the walls are clunch and flint.
I'll get in touch with Nick. Removing the modern render won't be possible or at least not anytime soon so it would be good to know if there's anything I can do to minimise the damage. And also get some peace of mind that the whole thing is not going to collapse

 

[Flyfisher]

The house is around 250 years old, suggesting it is substantial enough to have lasted that long, and is built from materials common to hundreds/thousands of buildings in that area of the country, which have also stood a similar test of time. Yet, the cracks in question have appeared very quickly in comparison to the age of the building and are more or less contemporary with a new heating system, which will have made quite a large change to the environmental conditions within the house, particularly during this first winter after installation.

Based on this, I would tend to agree with AndyZ that these small cracks are just the house seeking a new equilibrium after the change to its environment . . . except that "the ground floor became more uneven" sounds rather more worrying - not only because it's harder to imagine a new heating system causing such an effect but also because it must surely be more difficult to notice such a change in a floor that was already "uneven to some degree" compared to noticing some hairline cracks in a decorated wall? Implying a more drastic change in the floor than in the walls?

We're not far from Lakenheath and part of our house is built from the same materials, with only 'historical' movement evident in some places and nothing having been noticed in the past 10 years or so (despite significant changes to the heating system and occupancy), plus there are hundreds/thousands of similar buildings in the area built of the same materials and of the same vintage so I doubt there are fundamantal problems with such constructions.

As the house had a 'structural survey' relatively recently, it might be worth contacting the original surveyor. I appreciate there are many degrees of thoroughness when it comes to surveys, and their experience of older properties, but it was a recent professional opinion and if the worst case does unfold then there may be a case to claim against them.

As for recommendations for local specialists in period properties, I've previously used Stuart Armitage from The Morton Partnership, who coincidentally will be visiting us again next week to assess a problem with a badly decayed joint between a main ceiling beam/wall plate/A-frame . . . but that's another story!

 

[Kearn]

Thanks!
Re temperature/humidity - various materials contract/expand at different rate when temperature and/or humidity changes so I thought that as the house interior is now less humid and warmer, as the temperature drops outside it can result in cracks... I may be wrong though...

I wasn't saying it wasn't linked, as I would expect it is and the evidence points that way - more thinking out loud via my keyboard!! :roll:

Floors are mainly wooden laminate on god knows what... probably concrete but I'm not sure.

well, heat and moisture changes can impact old seasoned wooden boards, and I have no doubt laminate would respond faster and more dramatically!! Is it just the boards shifting or a more fundamental movement underneath...? :shock:

 

[Flyfisher]

Floors are mainly wooden laminate on god knows what... probably concrete but I'm not sure.

well, heat and moisture changes can impact old seasoned wooden boards, and I have no doubt laminate would respond faster and more dramatically!! Is it just the boards shifting or a more fundamental movement underneath...? :shock:

Ahem, I missed the bit about wooden laminate flooring and for some reason was thinking of a solid floor when typing out my previous post. In which case, I entirely agree that Kearn's question is fundamental!

 

[AndyZ]

Thanks for the replies and advice! Much appreciated.

Regarding the laminate flooring - it's not like there's a sudden huge difference. When we moved in the floor was already noticeably uneven - in some places you could feel a slight bump, while in others it the laminate would spring down as you stepped on it. The survey highlighted that the 'laminate flooring is poorly and unevenly laid'. There were no other comments or suggestions that this may be part of a bigger problem. These bumps are now more noticeable but that's about it... there are no holes/gaps between the panels, no cracks appeared etc. I don't know what's under the laminate but as this part of the house wasn't originally designed as living space, I've got a feeling that there's just some compacted soil and a bit of concrete there ;-)
And regarding comparing noticing the changes in the floor vs spotting hairline cracks - most of those cracks I would never notice or at least not so quickly if not the fact that after the first few appeared, I started looking for anything new/unusual.
Once again thanks for all the advice!

 

[88v8]

Straight cracks are shrinkage. Decorative issue, leave until Spring, then fill. I say Spring, because the RH will be at its minimum and the shrinkage at the maximum. After Spring, the cracks will start to close up a little as the RH increases.

What temperature do you run the heating? That said, 60% RH should not be injurious in the long term.

If the floor was laid over a solid floor or damp sub-surface because someone 'wanted a wood floor' then throw it in the skip. Take it up next year and have a look.

All this is annoying when it's your first house, but as FF said, it won't fall down.

Ivor

 

[AndyZ]

That's what I thought/hoped for. I noticed this last winter as well - cracks appeared at the beginning of the Winter and then closed up a bit in the Summer. The reason why I'm slightly worried this is because there's loads more of them.
The thermostat is set to switch off the heating usually around 17-19 degrees. RH tends to be around 50-60% recently.
And thanks for the advice regarding the floor

 

[Flyfisher]

If the cracks closed up a bit during the summer then I'd guess it's probably not a subsidence-related issue and just a bit of seasonal movement exacerbated this year by the new heating system. What to do about it will depend somewhat on how you feel about it. If it is stressing you out with worry (understandable if this is your first experience of a period property) then having a good structural engineer/surveyor to have a look could be money well spent. Personally, I'd give it another year to allow the house to fully reach its new equilibrium after the changes you've already made and then see how things stand - but that's a purely personal and non-professional view that's merely based on my 12 years experience with just one period property that had many more and far worse-sounding problems to which I've become fairly blasé because the house seems to have survived until I finally got around to fixing them. I'm sure not all old properties were well built, but those that survive today are the ones that didn't fall down over 200, 300, 400+ years so they are likely to have been among the better built and/or better maintained ones! :wink:

 

[AndyZ]

Thanks! I will wait another couple of weeks to see if it's getting worse/changing etc. I will probably get another survey done but may hold on with it a little bit.