Help My House Is Falling Down!

[Daffy D]

About a year ago we had a small extension built. Being subject to the exchange rates it was a Cheep Charlie kind of job but seemed to be OK.

The problem now is the joint between the concrete corner posts and the cement bock walls. There is a gap that has appeared.

It seems that the wall is not tied into the posts and with a push may fall over. I was watching them when they were building and saw they did stick re-bar into the posts to hold the wall but obviously did not watch them all the time.

The re-bar they used were just smooth rods, left over from the pathetic foundations, so the wall may simply be shrinking away from the post but still held from falling.

The gaps between the wall and posts are very small, about the thickness of a thick piece of paper, but you can see daylight through them.

The gaps are too narrow to fill with cement so plan to repair them by pumping in mastic, but was wondering if there was some product out there that I could pump into the gap that would bond the walls to the posts. A sort of cement/concrete epoxy that would help to bind the walls to the posts and stop them falling down if I were to lean on them.

Any usefully suggestions welcome

DD

[trogers]

Some photos may help. I suspect the cause of the cracks is differential settlement between old and new structure, and the worry is that the extension is supported only by shallow piles, resulting in further movement and widening of the cracks.

Is the floor of the extension sloping away from the old floor? Pour some water on the floor at that junction and check its flow direction.

Edited December 16, 2010 by trogers

[transam]

They don't use proper wall ties, just what's laying around. Sounds like you got a bit of settlement, depending on your out board corner support column concrete pads it could get worse if put on soft ground. For now run a bit of clear frame sealer down the crack so you can keep an eye on it and see if it gets worse.

[Pib]

Putting some Sista F134 Acrylic Elastic sealer should work. It' is highly elastic...more so than regular silicone, and is paintable. It also more fluid than regular silicone which allows is to get into smaller cracks. I've been using it for over a year now to seal leaks in my window seals, plastic awning connections to the house, etc. It takes about twice as long to fully dry (approx 2 days) compared to silicone which takes about a day to fully cure. Excellent stuff...I'll never use standard silicone against to seal leaks/cracks around the house. You can get it at HomePro, Global, HomeWorks, and other places...I've seen it in a few Lotus stores. It cost about 130 Baht per tube. Good stuff.

http://www.topvs1.com/catalog.php?idp=3803

[sezze]

Happens many times in Thai houses . Some pics will help to see if it has the chance of collapsing . Possible solutions are not very obvious because depending on many variables . Most times it is settlement of the ground but there are different reasons possible . I've seen buildings 20 years or more having them from day 2 and still going strong and others are very wobbly with a chance of collapse from day 1 . If the gaps are not getting wider , you might use the Sista thing like Pib said , but if is is getting worse .you might consider a redo . Also something worth considering is putting up a 2th wall infront of the previous with decend bonding to the concrete . This should be quite cheap as the blocks are cheap .

[transam]

Happens many times in Thai houses . Some pics will help to see if it has the chance of collapsing . Possible solutions are not very obvious because depending on many variables . Most times it is settlement of the ground but there are different reasons possible . I've seen buildings 20 years or more having them from day 2 and still going strong and others are very wobbly with a chance of collapse from day 1 . If the gaps are not getting wider , you might use the Sista thing like Pib said , but if is is getting worse .you might consider a redo . Also something worth considering is putting up a 2th wall infront of the previous with decend bonding to the concrete . This should be quite cheap as the blocks are cheap .

Unfortunately if the outboard corner uprights are on soft ground you cannot do anything untill they have settled. Adhesion of block joint cement to concrete up rights never really happens 100%. Rely on none movement.

[tangcoral]

We had two different extended 4 meters out each about month ago so nothing has settled yet.

Had an inspector come and warn us that they will both sink and eventually form a gap within 5 years time.

He said, an old structure joined with new structure will do this, thus needing proper piling depth and foundation.

But to slow the widening of gap he suggested we add a 2cm thick steel plate, ours is 20cm by 40cm long and bolt it to the two adjoining top corners on each side. Dont know how much help this is, but the idea is to greatly slow minimize the widening of gaps.

Anyone can chime in here is this suggestion is valid.

[trogers]

We had two different extended 4 meters out each about month ago so nothing has settled yet.

Had an inspector come and warn us that they will both sink and eventually form a gap within 5 years time.

He said, an old structure joined with new structure will do this, thus needing proper piling depth and foundation.

But to slow the widening of gap he suggested we add a 2cm thick steel plate, ours is 20cm by 40cm long and bolt it to the two adjoining top corners on each side. Dont know how much help this is, but the idea is to greatly slow minimize the widening of gaps.

Anyone can chime in here is this suggestion is valid.

I prefer to detail the joints between new and old around the assumption of long term movement. I will not use any hard fill material, but use foam instead to fill the gap (min. 5mm gap size) and then cover the joint line with removable Viva boards 20-25cm wide running vertical from floor to ceiling, and painted to match the wall.

If there is worry that the detached end of the wall has no vertical bracing to the floor, and thus may collapse due to lateral loads, a new concrete post may be added to this end, independent of the post on the old structure. Just do a neat vertical cut to the blockwall using a disc cutter, add in rebar, bolted onto the floor, close with formwork and concrete poured.

Edited December 16, 2010 by trogers

[Daffy D]

Thanks for all the replies with suggestions.

The problem obviously is settlement of some sort. I have been watching it for about a year now and the gaps don't seem to be getting any wider so maybe it's settled enough.

I'm going to wait another few months now with dry season coming and ground shrinking possibility and see how it goes. If the gaps don't get any wider I will the fill them in but as mentioned in the OP I was wondering if there was some sort of cement glue I could use instead of ordinary mastic that would help hold the joint.

Most things are glued together these days including aircraft so there should be something to stick cement together.

I was exaggerating a bit about leaning on the wall and it falling over. It seems sturdy enough probably held one or two ties that stop it falling out-wards or in-wards but I'd still like to pump some adhesive in there to help the wall adhere to the post.

"tangcoral" I have though about bolting some steel plates to the top corners to hold the wall to the post but will wait a bit longer to be certain the whole thing has actually finished settling completely.

Thanks "PIB" that Sista sealer sounds interesting, will check it out.

Cheers

[Pib]

I prefer to detail the joints between new and old around the assumption of long term movement. I will not use any hard fill material, but use foam instead to fill the gap (min. 5mm gap size) and then cover the joint line with removable Viva boards 20-25cm wide running vertical from floor to ceiling, and painted to match the wall.

A method such as this is about the only real way to make the crack disappear. Sealing with Sista F134 or using the foam will do a great job of keeping water and insects out, but even if you paint over it you will still probably see a sealed crack. And even if the crack is hairline and the paint temporarily makes it disappear, it won't be long....few months at most....before more movement occurs and you see a hairline crack in the new paint although the sealant is still intact since it's very flexible....even those paints that claim to stretch a lot. Yeap, to make the crack disappear since it's still probably growing for a long time to come, a person would need to cover it like you mention above. Depending on the crack's appearance (i.e., straight, zigzag, etc) , sealant/foam topped with paint may look fine...almost like a cement joint between wall cinder blocks. I've seem many, many cracks like the OP mentioned from add-on construction....ain't a lot you can do other than seal them, and then if desired, hide them with some type of covering.