These questions were sent to a friend who wants to engage a building contractor.
The project involves is a high networth project, so he is not ready to use an incompetent or inexperienced contractor, so I have to draft out simple questions that can make your contractor either edgy or keep him in check. Is good to know you aren’t a complete dumb, when it comes to building your house, asking so much question will also make the contractor knows you won’t accept a job not well done. In all this is just to start a conversation with your contractor by sheepishly asking everyday site questions.
(1) What are the types of foundation?
-strip, pad, raft and pile
(a)What are the advantages of one over others?. He should be able to explain a little.
-Strip is the common one that follows the path of walls, pad is also knowned as isolated foundation, raft is of concrete spread round the site often time in form of inverted T, also used for waterlogged or loose soil that is of moderate few floor height. Pile is concrete bored deep down the floor usually for multiple storeys.
(2)How do you assure or determine that the foundation is squared, what will you use?
– An instrument called square, details more
(3)Explain how to set out the building?
(4)What is the thickness of foundation concrete bed you will use, let him show you from the structural drawings. Could be 600mm(2ft)-1200(4ft)mm or more.
(5)What are the likely mixture ratio for the foundation concrete?
-1:2:4, i.e 1 bag of cement to 2 headpans of sand and 4 headpans of stones.
(6)Granite or gravel which are you going to use for the building, what are the differences?.
-Granite is fine neat and stronger but far costlier to gravel, granite bonds easily because of less impurities.
(7)The iron rods where are you going to buy them from?
They said imported iron rods are often stronger why?
-Some iron rods in Nigeria are recycled hence they are often not as strong, though the ones from factory in Delta are ok.
(8)Why do you put biscuits (small cubic concrete square around iron rods when laid in concrete mass during construction? What are biscuits anyway?
-To allow the iron rods to be properly buried inside concrete, if the rods are exposed to weather or climatic elements they may get rust and that will weaken them, apart from that the exposed one is not fully functioning optimally.
(9)What is oversite concrete? Let him explain
-German floor in lay man’s term
(10)What is the height or depth of groundfloor between the top of the adjoining road to the ground floor? What are the advantages of raising the ground floor higher.
-Of course it will help in case of flooding, you can easily slope the site to your drainage points.
(11)Load bearing walls, retaining walls, nonloadbearing walls, what are they and the differences in a building?
-Loadbearing walls as the name implies helps in carrying the load of the building, it also contributes as structural part of the building .
-Retaining walls are for supporting other structures in place, for example in arunoff of water, retaining walls can be used to protect the sands or earth from being washed away by your fence. It could also be used in basement.
-Non loadbearing walls are others in a building that aren’t really contributing structurally to the stability of the building, like the curtain walls, partition walls in a building.
(12)If the place is prone to flood what are measures you can use to check or forestall water from percolating through to the building.
-You can use dpc membrane (cellophane like stuff to prevent water from percolating thorough to the building.) What is DPC anyway?
(13)What are the advantages of using oversite concrete or german floor?
-It helps reduce water percolation from ground
-It enhances the strength of building
(14)The suspended floor slabs- first floor, second e.tc what mixture ratio is advisable to use.
-thickness of suspended floor-150mm or 6”
What type of suspended floor are we using?
– Most likely solid- that can be seen from the structural drawing
(15)If you discover the roof leaking after building what are the possible causes and how can you remedy it.
-If the design is faulty
-Bad workmanship by installer
-To repair, relay the very terrible ones,
You may apply aluminium flashing for aluminium roof. Other areas close to wall you can use bitumen too.
(16)The roof, are you recommending aluminium or others, what are the advantages of aluminium over others.
-Is probably going to be aluminium and advantages-it is light, durable and aesthetically pleasing to others, you can choose any colour.
(17)Conduit wiring or surface which will you advocate?
-Conduit is when you have wires embedded in walls.
-Surface is when it is placed on surface of walls.
Conduit is preferable for office settings it is neater, though surface can be easily maintained.
Pls assist me on how to design a slab beam nd colum nd to calculate d amount of planks to be used for a decking too