Browse Forums Building Standards; Getting It Right! 1 May 02, 2011 11:26 pm Hi Everyone, Need opinions/suggestions/ help please... My house built on strip footing, entrance has 8 steps and from garage there are steps as well. Land we bought has a highslope, and we pay for 20K for the site cost. Builder recommend to have a strip footing foundation which we dont have much idea about it. Builder said cost of this foundation is quite expensive than normal one, and the site cost that we paid is not enough. Can you please help or does anyone know the disadvantages of strip footing... Is house cracks (corniche/wall) one of disadvantage? Thanks Re: House built on strip footing- advantages & disavantages? 2May 03, 2011 7:05 pm Strip footings (with suspended floors) can be lowest cost method of building on steep slopes as slabs get very expensive once have to be stepped. As long as the footings are correctly designed they should be OK. The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: House built on strip footing- advantages & disavantages? 3May 03, 2011 7:10 pm Thanks for your reply .. just got another question with this kind of house foundation, if they builders not doing it right, would it cause house cracks? Thanks! Re: House built on strip footing- advantages & disavantages? 4May 03, 2011 7:12 pm any house not built right can crack. The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: House built on strip footing- advantages & disavantages? 5May 03, 2011 7:23 pm OK, go back a little. It is NOT the builders decision to advise on the structural foundation of the building. You need a Structural Engineer to give that advice. The Engineer will assess the site and advise and provide drawings. This advice will be based on the Geotechncal Survey provide by a Geotech Engineer. Ask the builder to provide both the Geo Survey and Engineer drawings so you can see them. If they dont, dont let them build your house!!! You would not believe how many houses have been built on footings "designed" by a Fat Bloke on an Excavator. Re: House built on strip footing- advantages & disavantages? 6May 03, 2011 7:49 pm Hi Builder Paul, So unfortunate that we had decided to build our house in strip footing as far as I recall I didnt notice the foundation variation signed by a geotech engineer , but I will double check. House built 2 years ago, and I found a lot of cracks thin and thick lines from corniches, garage wall, toilet wall is this because of the foundation? Whenever we walk downstairs doors are shaking... We still have their building insurance till 6 years , can we complain to them about these? .. Can you give any suggestion what to do or can I ask Kevin Mcdonald to check again ? Thanks Re: House built on strip footing- advantages & disavantages? 7May 03, 2011 7:52 pm I'm confused. Is this a new house that needs footings, or a 2yo house that is cracking? Re: House built on strip footing- advantages & disavantages? 9May 03, 2011 8:12 pm Ok, post some pictures, drawings, anything you got. Dont forget a suspended concrete slab can bounce as much or more a timber floor, and still be sound. Might just need to stop the deflection. Re: House built on strip footing- advantages & disavantages? 10May 04, 2011 7:25 pm Since you're in Melbourne, there's a good chance you're on clay soil. Thanks to the 10-year drought followed by record rainfall over the past year, there's been a lot of soil movement, and gaps in skirting/wall and cornice/wall joins are common. If those are what you're talking about, it may just be normal movement. If you have cracks through the middle of sections of cornice or sheets of gyprock though, that's not normal. Perhaps you can elaborate, or post some photos? Re: House built on strip footing- advantages & disavantages? 12Sep 25, 2016 10:24 pm Strip foundation is a continuous concrete strip on which load bearing walls are built centrally. This represents a level base for the walls and its dimensions must be sufficient to allocate the load imparted to the foundation to subsoil area capable of supporting the building weight without excessive compaction. Today, for foundations developers mainly use concrete as it is easy to place, spread and level in the foundation trench. Due to its ability to harden concrete creates a basis for walls and develops proper compressive strength to support the foundations’ load. Previously, strip foundations were made of brick. They were installed directly onto firm subsoil or erected on a bed laid of natural stones. What is strip foundation width? It is predetermined by the bearing capacity of soils and by the alleged load. The greater load bearing capacity of the soil is the less the foundation width is needed for the same design. If the strip foundation should be built on a sloping area, you will probably need to create a stepped structure. In order to properly step the foundation, total thickness of the top part of the foundation should be double the step height; or it must equal to 12 inches, if greater. To avoid possible need to cut blocks or bricks as well as to ensure stability of the future wall, the brickwork or blockwork performed later on is to tie in directly at the step. Deep strip foundation is known as the most used type and it is the cheapest method when the soil conditions are appropriate. A strip of reinforced concrete supports the walls. Depth of the trench can range, although it should be at least 40 inches deep 24 inches wide. The minimal depth of concrete should be 9 inches. The foundation width is determined by the specifics of soil but the conventional minimum is 18 inches. However, your builder is likely to specify 24 inches; this is a conventional width applied for construction of two-storey houses. Wide strip foundation. Foundation structures built on subsoils that have poor bearing capacity, for instance, soft sandy clays, must be significantly wider than the traditional strip foundations as it is necessary to allocate the load to a greater area of subsoil for higher stability. Excessive increasing of the width and depth of the structure in order to prevent wall shearing is not economically grounded. A reasonable option is to build a foundation using reinforced concrete. Reinforcing bars add tensile property to the foundation making the whole structure capable of withstanding tension and compression affect. Advantages and disadvantages of strip foundations Strip foundation has both positive and negative qualities. The positive may include simplicity of design, the possibility to build the foundation without expensive tools as well as its long-term operation. The negative qualities consist in a comparatively low durability, high cost in the final stages of construction (you must perform additional manual work, such as filling soil between the strips and its leveling, building floor and so on), inability to make monolithic binding of the floor to the basement. When can a strip foundation be used? Concrete strip foundationYou can look through the building regulations to find out conditions under which strip foundation can be used. Note the following in detail: When planning the construction, consider the required width of the foundation strip denoted in building regulations. The concrete solution should meet the requirements of compatibility with the soil chemicals. The thickness of the concrete strip should equal to or exceed the projection of the external side of the wall, but not less than 6 inches. The step height shouldn’t exceed the thickness of the foundation. The foundation strip protrudes beyond the edge of piers, chimney forming side of the wall as much as it protrudes beyond the exterior surface of the wall. yep sounds good make the footing bigger to to allow for the pipe in the middle 3 7326 PM me your email. I have a build excavation calculator you can use based on your plans to double check what your builder is telling you. Cheers Simeon 1 10247 I've dug some footings to embed a post anchor into. My holes are around 450mm deep which I'll put a 200mm stirrup into. The bottom of these holes seem firm enough. … 0 3323 |