New construction on old foundation??

I have demolished my old home and going to reconstruct on same place. The contractor i hired and even my architect has advised me not to dig old foundation and rebuild on same foundation. They advised me to lay a beam on old foundation and start my 9 inch wall on it. What do you guys suggest? Should i dig the whole foundation rite to the bottom or lay a beam on old foundation and start new building?

@HT @ARAMCO

please suggest!

Dear fahad,

first of all please inspect all foundations carefully.

If you observe any foundation crakes or damages then go to repair.

After repairing of foundation you can start work on foundations.

9" to 1'plingth beam is enough,it is safe and secure for your new structure.for more strength use 3" thick 2nd dpc with 2 steel bars tied on 6" to 9" center to center.

Thanx and regards

muzafar mirza

AOA,

As mentioned by Mr.ARMCO Inspect the foundation. Plinth beam should be good enough to withstand the weight of the building.

For additional strength get the rings made after every 6 inch rather than 1/1.5 feet gap for the plinth beam. This would multiply the strength of your plinth beam by 4 to 5 folds.

Most important point is dig at least 3 to 4 feet for pillars to be reinstalled. If that is neglected than alone beams may not provide the strength required.

I am agree with my respected friend @ MR HT.adding of rcc coloums in foundations will be give a extraordinery strength to main structure.

Thank you much ARMCO and HT. Jazakallah both of you.

ARMCO sir i did not understand "use 3" thick 2nd dpc with 2 steel bars tied on 6" to 9" center to center." can you please explain a bit more.

To my knowledge, 2nd dpc is laid where there is floor difference. How it is concerned with strength of building?

Dear fahad,

using of 3"thiked reinforced dpc working as a strip beam or a bed plate.it gives us a 2 time more strength with a single plinth beam. Lay your plinth beam on NSL (naatural surface level) and dpc on ffl (finish floor level).now a 9" thicked beam gives us a strenth of 24" thicked beam.9"plith beam + 1' brick work upto ffl + 3" dpc = 24"

You need to inspect it first by contacting any reliable architect or contractor first. Without visiting that place, it is not so easy to understand.

Usually, it is not recommend by architects that you construct on the same boundary but condition can be good as well in some cases. Amer Adnan Associates is a good name in this field to get idea and knowledge about this procedure.

If old foundation suits your new construction need and homes are constructed on both sides go with same , else dig out all. Do not waste money on repair , either its ok for construction or not .if on sides plots still present , foundation r loose do not repair onconstruct