Browse Forums General Discussion Re: 3 Year old slab moving, now blamed on Landscaping 26Oct 17, 2011 7:48 pm Some people apparently have nothing better to do than comment on other people's sigs. Re: 3 Year old slab moving, now blamed on Landscaping 30Oct 17, 2011 10:03 pm B STAR Aiah, why would you prefer a wafle slap on a p class site. At least with a raft slab it can be designed to rest on solid soil. Wafle will just sink over time and the soil around it erode. Also Raft slabs dont require the 1 meter concrete around the edge of the house. I don't see the logic in excavating into a highly reactive site and encasing large sections of it inside a raft slab. Both a raft and waffle slab should be resting on piers to the same suitable material, the waffle slab is isolated and sits above the P site, while the raft is quite literally dug into it. Either slab properly designed and installed will do the job, I just prefer waffle. Re: 3 Year old slab moving, now blamed on Landscaping 31Oct 17, 2011 10:11 pm I didn't think that ag line is supposed to be beside the footings! I thought it should be a "safe" distance, but so far I've been unable to define "safe". I assume 2m is safe. Apparently, from what I've read (and possibly due to workmanship issues): 1) ag trench can act as a water run, meaning (I think) that water would travel too close to the slab if trench is beside the footings; 2) ag pipe can drain the soil "too much". These 2 issues are actually opposing (ie. theoretically they should negate each other out), therefore my utter confusion with this My signature is distracting people from my wise posts ... Re: 3 Year old slab moving, now blamed on Landscaping 32Oct 18, 2011 1:19 pm catjim Adam.M Now once you have entertained all of these issues and installed preventative measures, your house is still sitting on a slab that is less than the thickness (between 85mm - 100mm for a single story) of the front footpath. AND it's sitting on 450mm footings with styrofoam voids? What it boils down to is that YES, the builder should have ultimate responsibility for your houses structural integrity. But all in all as consumers of houses, we shop around and buy best valued house (sometimes cheapest). Builders meet this need and build us the best valued house which contains a 85mm slab, styrofoam voids and prefab roof trusses. All of this on P clay type sites which happens to be a majority of the west of Melbourne. See what I mean? Does this mean that these problems are more likely to occur to a waffle pod slab as opposed to a raft slab? As Aiah said, incorrectly engineered or installed foundations of any type will cause issues. The idea of a waffle slab is to allow for "movement" especially on a P (Problem) class soil. BUT, this is where everything else does not always follow the same concept when it comes to building the house itself. This is where you can stick it straight to the builder and is something we have not covered within this thread. At the same time, improving the reduction in water near the slab should give you the largest benefit (unless there is a fault in the slab itself. So if you have a waffle slab that allows for "movement", having the following will not help the structure of the house: a. No articulation joints (standard these days) b. Incorrectly installed articulation joints - not at the appropriate areas or too far away from each other c. Mortar in the articulation joints d. Cornices screwed both in the ceiling and wall - standard practice but does not follow the "movebility theory" e. Water against the foundation - I think we have covered that enough f. Lack of clearance between the bottom of windows and brickwork (5-8mm or so) g. Cracked or leaking stormwater pipes under foundation h. Timber trusses incorrectly installed i. Timber shrinkage j. lack of clearance between door and door leaves (if outside of 2mm & 5mm) k. grout used between tiles instead of sealant l. incorrect placement of the rio in the slab (concrete cover) m. builder not following specifications n. or just plain old badly engineered houses Re: 3 Year old slab moving, now blamed on Landscaping 33Oct 18, 2011 1:59 pm Hi. How wide are the step cracks in the mortar? f they are only hairline nothing will be done about it! They need to be 2 to 3 mm wide. Re: 3 Year old slab moving, now blamed on Landscaping 36Oct 19, 2011 12:13 pm JimmyL How the hell will a 1m path stop water going under the house? Water will find a path and 1m is not enough to make a difference. To expand on the other reply to this: Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ If the path doesn't allow water through it and has adequate fall the fall will carry the runoff away from your slab. If you have a drain below that fall then you can carry that water further away again. The fall is not accurate in teh picture either. 1:20 means that a 1m wide path would finish 5cm below where it started. Not a lot but more than enough to get water running away from the house. Re: 3 Year old slab moving, now blamed on Landscaping 37Oct 19, 2011 2:27 pm not a big slope you have there mate. get engineer to check your slab instead. is your grass area always wet? with pool of water or the mud never get dry? a drainage pipe lead to no where, i.e. not connected (don't laugh it happens) could soften ground around your slab. a soil test will tell what is the difference between the current state and the previous state before building the house. Re: 3 Year old slab moving, now blamed on Landscaping 38Oct 19, 2011 5:59 pm That area is never wet (thats why the dog has a dog door there) but there is a layer of gravel i put down on top of the surface left over from the driveway. I dug down 30-40cm the other day and it felt like moist clay but not soggy or pooling. What do people expect the ground (clay) to be like at that depth? I might try dig somewhere else that is less likely to be affected and see Re: 3 Year old slab moving, now blamed on Landscaping 39Oct 19, 2011 9:24 pm I was very surprised to see that some 5-10 cm below the top, the soil is still very much moist. Chris, how do you ensure that the water runs into the drain and not in between the path and the drain? Should there be some really good seal ?? My signature is distracting people from my wise posts ... Re: 3 Year old slab moving, now blamed on Landscaping 40Oct 22, 2011 11:09 am Can I just buy into the arguement here.Jimmy I am in williams landing having the same problems as you. My block is built up a fair amount and has slope well above what is required. We have had a very serve case of cracking in the house and slab movement. less then 2 years after moving in. I also own a rental property in tarneit, just up the road no more then 3 km we built almost 5 years ago. the edges of the block slope back towards the house and we have never had a problem with any cracking. Neither place has had concrete paths. Ive done a walk around my neighbours houses asking about the problems with cupping. I can tell you at least 50% do with mine being the most serve. It didn't matter who had paths or gradens around the property and have to say a lot of them had a common builder. Have a walk around your neighbour hood and see how many people have a continous 900 mm path around the house including the front. I think youd be lucky to find 1 in 50. The reality is even the engineers have no real idea how to prevent this. Hence it is happening. In mass. Push the issue with the builder, if they try to blame your house offer to walk around the neighbourhood with them and knock on peoples doors and ask them if they have the same problems. You will prove your point very quickly as I did. The end of the day we all paid those massively over priced site costs only to find out the slab where not sufficently engineeered. my 2c Total Breeze Air Conditioning and Electrical - Based in Melbourne http://www.totalbreeze.com.au Your house roof does not show rusting other than some surface rust on the flashings. In my opinion you dont need to replace or paint the roof other than treat surface rust… 1 10216 Hello everyone, I have a question regarding moving a chandelier after it has been mounted. The chandelier in question is quite large, measuring 4 meters… 0 72341 9 24814 |