Bumpy floor

[Befals]

Just purchased a late 70's house. The homebuyers survey commented on the uneven floor in the living room, but because of the fitted carpet they couldn't investigate fully. It stated it was likely to be caused by layering of carpet/underlay, but that we should investigate before committing to buy (which obviously we didn't as didn't want to ask the seller to rip up the carpet).

We've now pulled up the carpet, in preparation of having it replaced, and there is an obvious ridge running down the middle of the living room. You can't really see if from photos, but you can see the bulge if you look closely, and feel it underfoot.

Do we need a builder in to look at it, or a structural engineer? My partner wants to just get the carpet laid over it, but that doesn't seem like a good idea, particularly as it's not a cheap one we're getting, I read uneven floors can cause uneven wear and tear.

There's also an issue with the drainage pipe which runs along the front of the property (outside the living room). We had a drainage survey which showed a root entering the pipe, although this is not directly outside our property, but is under next door's front garden. There's also evidence of ground movement to the side of the house, which is why we had a CCTV survey. The survey showed that the drainage pipe running along the side of the property was holding water in the pipe which suggested the pipework has moved to cause this. We still don't know if the ground movement is caused by leaking drainage, or something else, which has caused the pipework to move.

The house shows no sign of movement or cracking, but the concrete driveway to the side is cracked and showing signs of ground movement, and the detached garage is badly damaged. This is set away from the house and not near the living room which is on the left side of the house, and the driveway / garage is on the right side, but now I'm concerned that the flooring issue could be connected.

Anyone have any advice?

Are you in an area where shale floors might be a concern? I think they are mostly found in the north east. I would want the cause investigating in case it’s linked to the movement ‘ drainage problems

I don't think so, I'm just outside Cambridge.

Bump

I think you should get a structural engineer in. Did you have a full building survey? I'm surprised the surveyor didn't recommend one considering the ground movement.
Do not just carpet over - the issue will not go away.

You should get it checked out - those tiles may have asbestos in them also by the way - I'm no expert but our tiles did and they looked like those tiles

We got a homebuyers survey, I tried to book a full building survey but the company pursuaded me I didn't need one as the house wasn't old enough/didn't have obvious issues (we hasn't realised the cracking was sign of ground movement, just thought it was age). The survey said the ground movement was likely drainage issue or tree roots and that we should get a CCTV survey of drainage, which we did. This just showed that water was sitting in pipe so they said it has likely shifted (presumably from the ground movement).

The root at the front is nowhere near the cracking. Looking at historical google maps looks like there were some trees the other side of the fence a few years ago but the car didn't go close enough to get a close look (end of terrace). According to the seller this cracking has happened within the last year (he said didn't know cause, assumed it was from age) There are some large trees on neighbouring land to the front of property, but no sign of cracking in the concrete near them, just towards the back side where there is only some small shrubs other side of fence (6ft and under).

Like @custardbear the first thing I thought when I saw those tiles was asbestos, my parents also in Cambridgeshire flooded in December and the insurance company insisted that the tiles in the whole of the house were removed by a specialist before the builders could be sent in to work on the property. It is also a 1970s house, their tiles were same but in green.

Has the house been flooded in the past?

How did you deal with your tiles? Did you remove? Sorry to jump on someone else’s thread but I’ve just lifted my bathroom floor and found those tiles underneath.

We had a similar issue in a 1960’s property, it turned out to be copper central heating pipes that someone had tried to lay asphalt over, not sure what they were thinking, needless to say we rerouted them.

@Cissyandflora the insurance company organised removal of the tiles.

@Cissyandflora call a specialist asbestos company and ask them fir a quote and sample test to check if it's got any asbestos in it

Those are almost definitely asbestos tiles so would look into removal or covering with something sturdier than carpet anyway.

is this a concrete ground floor?

it looks in the pic like plastic tiles stuck down on it. Sometimes they contain asbestos. If there is a loose corner you can snip it off and send it away for testing.

These are called Marley tiles. They are common in 1970s houses. I think they were used to provide some damp/waterproofing.
You can read about them online.
The problems arise if they are broken or brittle as they can then have loose fibres as they do have a low level of asbestos.
They are also stuck down with bitumen which is difficult to remove.
Mine were in good condition and my carpet fitter was happy to put new underlay and carpet on top. I wiped them first to clean as they had been under 45 year old carpet.
They were laid on chipboard rather than floorboards and the floor did have some bowed areas which furniture covered ok.
I think your decision will depend on how badly the floor is bowed and how damaged the tiles are

I don't know what's under, the survey said the flooring was concrete so was expecting to see that, not tiles. Although I don't know how the surveyor knows what it is if they haven't looked under the carpet, do they research the builder? Or make an assumption due to the age and style? It mentioned possible asbestos in other areas but not the floor so just didn't think. Wish we'd left the carpet down now while we were stripping paper. We've been sweeping the paper off the floor and the mess from the ants nest we found under the carpet by the patio doors the kids have been running around in there and helping us strip the paper too... Hope we haven't exposed them to anything. I read the risk is low from tiles but the carpet strips have been nailed into them so a small risk of dust I guess.

Will add asbestos testing to the list if things that need to de done! The carpets supposed to be fitted on the 21st, and we've planned our moving in around that. No idea if I'll be able to get the floor sorted before then

@Befals if you have to go through your insurance it is unlikely to be fixed on that time scale, but f you are going to access below them they will break and then have to be removed......

If there was nothing wrong with the floor I would be sticking my fingers in the ear and La la la ing.

It's whether the carpet can be fitted over the bulges... guessing not. We do need to get a structural engineer to check the garage anyway, so might as well get them to look at both problems at the same time. If it can be levelled off by putting something over the top of the tiles, that would resolve both the unevenness and the asbestos I guess.

I think it is more likely that there is a structural fault in or under the floor. You seem to have signs of subsidence around the house that may be relevant.

Sometimes this kind of hump is found when two rooms are knocked together, or an extension is added, and the floors are not at quite the same height.

In some districts, unsuitable material such as furnace slag was used as hardcore, and can expand over time, pushing the floor up and cracking it.

There's not an extension, there was possibly a wall between the living room and dining room originally, but the position of the bulging isn't near where the join would have been.

Unsuitable material may be a cause, would this be the case in Cambridgeshire? I can try asking if anyone else on the same road has had similar issues.

Someone else asked about flooding: not to my knowledge, and nothing was picked up by searches.

Is it possible the bulge could be caused by leaking sewer pipes, and If so could it cause it to bulge without the walls showing signs of movement?

good idea to ask neighbours with similar houses.

in the cases I've heard of, it can be an entire estate or development, put at at the same time by the same builder using the same materials and techniques, so local surveyors, builders and estate agents will know about it.

Sewer pipe is an unlikely cause, as I would not expect a 1970's house to have sewers or manholes under the floor unless it had been extended. But a leak can undermine a wall and cause subsidence.