Underpinning In Question

happyhero

Hi I hope this is the right place to put this, I saw previous underpinning questions were put in this area. I have lived in my 1930's house for 10 years now. Our neighbours have told us that previousowners to us had our house underpinned, which seems to tally with the original report we got when we purchased and the fact that there is a slight slope to one side of the house. The report we got when we bought said something about the fact that there had been movement in the past but it was stablised now, so we were happy with that.

In the last months or so we have noticed a crack about 3 feet long either side of our lounge/front room window, about 3" away from the wall edge closest to the window. Our lounge is wallpapered and therefore this crack has torn the paper to display this crack. Its only very thin ie about 1mm wide, about the usual crack you get.

If we have been underpinned before is there likely to be further movement (guessing that it was underpinned 15 to 20 years ago)? We live in a clay and chalk area in Surrey.

Would our insurance cover it?

How can you check whether there is further movement or how would a contractor do it?

How much does it cost to have done as a very rough guide?

Any info appreciated.

itsakidsworld

If the under-pinning has been done 15-20 years ago but cracks have just started to appear, then yes there is movement underground.

You should be covered by your insurance company. Call and ask them how to proceed.

They will authorise a structural engineer to report on the movement. What they will do is place little plastic strips over the cracks and moniter them for months. These strips will give them an accurate reading of how much the property is moving. Then they will do "pilot" digs around the affected area to expose the areas moving underground.

Under-pinning is a very hard and expensive job but if you are insured you will be fine. Make sure that if you are covered and it needs doing that they do the whol house with full insurance backed guarantees. This not only protects you but protects any future owners. The previous work may still be under guarantee.

silvercar

Its absolutely the right thing to contact your insurer but I wouldn't start panicing just yet. A crack only 1mm wide doesn't meant there has been significant movement. Rendering and plaster often crack over time; doesn't mean the house will need underpinning.

happyhero

Perhaps I should add that we had an attic conversion which is quite sizeable done in 2000. This was deffinitly done with all the correct structeral calculation. I really do believe we did the right things with making sure how this job was carried out, however I wonder if it could have added to any possible problems we are having now.

Also if we were to get a structeral engineer to look at it and they used these strips for several months (which seems the normal way to do it), how would the insurance company react, ie it could drag on over more than one insurance period? Wouldn't they try to wriggle out of renewing my insurance to avoid a big payout or make me not want to re-insure with them by quoting high? After all I would end up getting a lot more out of them than they would out of me.

Does your house policy normally cover underpinning generally? I will check.

The attic has a few cracks too but is that not like moving into a new house and having to put up with that as it settles? Nearly the whole roof was gone at one point when they were doing the attic conversion, so it was almost completly rebuilt and therefore I would say new.

The one thing that has puzzeled me since we moved in is how come you see no cracks on the outside wall?

itsakidsworld

It sounds like you have answered your own question here!!

If you have had an attic conversion then without a doubt you will have "disturbed" part of the building. If it was built correct as you say then the crack could be from a load bearing wall which is carrying the extra weight and so has re-settled.

Maybe it is in a position where the joists were fed into the roof and so this could have disturbed the inner section. If you have no sign of movement outside then I would feel confident enough to tell you that it does not sound like it needs underpinning to me.

Place a paper strip which you can make yourself over the crack in three places. Mark the strips first in 5mm marks upto about 200mm in total. Place one at the bottom, one at the top and one in the middle. Colour each 10mm section in a different shade. Then wait and watch!! If the strips start to split then you have settlement. If not then you have already had settlement!!

This is a very easy system for you to try and you do not need to alert anyone at this point yet.

silvercar

If you were to call an expert in, you would have to declare it if you moved insurance companies and chances are they wouldn't want to know. You would then be stuck with staying with your existing company.

My parents had a garage that had not been supported properly and had to be knocked down and rebuilt. Their current insurance company handled the claim but billed some of the costs to the insurance companies they had used previously. I can't remember if they went back 3 or 5 years. This is standard industry practice they were told. It certainly made the insurance company reasonably helpful as they were only paying out a proportion of the bills they were agreeing to. The garage is some distance from the house, so the house was not affected but they have not been able to move insurance companies yet.

happyhero

itsakidsworld wrote:

It sounds like you have answered your own question here!!

If you have had an attic conversion then without a doubt you will have "disturbed" part of the building. If it was built correct as you say then the crack could be from a load bearing wall which is carrying the extra weight and so has re-settled.

Maybe it is in a position where the joists were fed into the roof and so this could have disturbed the inner section. If you have no sign of movement outside then I would feel confident enough to tell you that it does not sound like it needs underpinning to me.

Place a paper strip which you can make yourself over the crack in three places. Mark the strips first in 5mm marks upto about 200mm in total. Place one at the bottom, one at the top and one in the middle. Colour each 10mm section in a different shade. Then wait and watch!! If the strips start to split then you have settlement. If not then you have already had settlement!!

This is a very easy system for you to try and you do not need to alert anyone at this point yet.

Cheers itsakidsworld, I understand about the strips ie one near the top of the crack and then middle and bottom aswell but your sizes are confusing me, 200mm is 20cm or about 8inches. Have you got your decimal points mixed up or am I missunderstanding you. Also you mention 5mm marks, across the tape across the crack I assume but the crack is bearly 1mm and if it reached 5mm I would be really worried, never mind multiples of 5mm. Or are you assuming that most cracks will open this amount ie you could have a crack over 1cm. It could be that I am over panicky about a very narrow crack and you are more knowledgeable about these things and maybe have seen some quite big cracks.

Can you put me straight on all this please? Also what would you do, use a bit of masking tape or superglue some paper across the crack?

Debt_Free_Chick

happyhero wrote:

Also if we were to get a structeral engineer to look at it and they used these strips for several months (which seems the normal way to do it), how would the insurance company react, ie it could drag on over more than one insurance period?

You don't get the structural engineer in - your insurance company does that. All you have to do is to register a potential claim with your insurance company and let them take it from there.

mike_the_bike_2

Have you any local authority maintained trees on a verge near you at all?...It may be that these if they have not been reduced may not be helping what is happening....

itsakidsworld

Happyhero,

Sorry if it was confusing. The strip size is correct and is 8 inches or 200mm as you say. They have to cover a bigger span to give an accurate reading. You could reduce to 150mm but the wider the strip the better the chance of getting the correct information.

Don;t use masking tape as this is to thin. Cut a strip from a bit of A4 paper and then stick drawing pins in the ends. You don't seal the paper on the crack. It is abit like an elastic band effect if you understand.

I still think you have nothing to worry about as 1mm really is nothing. Some new houses can have cracks upto one inch (25mm) after they have settled!!!! Not anything we have built I must add!!;)

silvercar

Anecdotely, if you can see daylight through the cracks you should be worried!