Slab dhalai se pehle kya check karein, concrete grade kya rakhein, curing kitne din karein — ghar ki sabse important stage ki poori guide.
Dhalai Se Pehle Checklist
Shuttering (centering) poori tarah level aur tight honi chahiye — koi gap na ho warna cement paste leak hoga aur honeycomb banega. Steel ka spacing, lapping aur cover block engineer se check karwaayein. Cover block 20-25mm ka zaroori hai, warna steel mein zang lag jaayega.
Electrical aur plumbing conduits slab mein pehle se daal dein. Dhalai ke baad chhat todna mehnga aur structure ke liye kharab hota hai.
Concrete Grade Aur Mixing
Residential slab ke liye kam se kam M20 grade (1:1.5:3) rakhein; multi-storey ya bade span ke liye M25 behtar hai. Ready-mix concrete (RMC) hand-mixing se zyada consistent hota hai — agar budget allow kare to RMC hi lein.
Water-cement ratio control karna sabse zaroori hai. Zyada paani daalne se concrete workable to lagta hai, lekin strength 30-40% tak gir jaati hai. Yeh sabse common site galti hai.
Curing — Sabse Zyada Ignore Ki Jaane Wali Cheez
Dhalai ke 8-12 ghante baad curing shuru karni chahiye aur kam se kam 14 din, ideally 21-28 din tak chalani chahiye. Slab par paani bhar ke rakhein (ponding) ya geli bori bichha dein.
Garmi mein agar curing chhoot gayi to concrete apni poori strength kabhi nahin pakad paata aur baad mein cracks aate hain. Yeh nuksan wapas theek nahin hota.
Shuttering Kab Kholein
Slab ke props (support) kam se kam 14 din tak nahin hatane chahiye; bade span ke liye 21 din rakhein. Side shuttering 24-48 ghante baad khol sakte hain.
Jaldi props hatane se slab beech se jhuk jaati hai (deflection), aur yeh permanent hota hai. Contractor jaldi kare to bhi is par compromise na karein.
