Estimating Waste Week 3 CTC-415

What is waste Waste is material that needs to be supplied but may not be used All material items except steel beams and columns have waste Needs to be minimized

Concrete & aggregate quantities Concrete work –Some can be precisely estimated – columns, walls –Some cannot – footers, sidewalks, anything bearing on ground –Concrete batched by weight not cubic yards May have variances due to sand and aggregate density Assume 3 – 5% waste for variances

Concrete & aggregate quantities Asphalt –Batched by weight –Assumes uniform weight for sand, aggregate and filler –Also assumes existing grade is precise and accurate –Assumes compaction is correct –5 – 10% waste

Concrete & aggregate quantities Sand and Gravel –Sold by weight –Based on bank volumes at pit –Based on loose volumes on truck –Based on compacted volumes at job site Need to know swell and shrinkage of soil –Can be 25 – 40% changes Need to know moisture content of soil

Masonry Can count block needed –Need to account for breakage Especially if cutting block/brick to size –5 – 20 % depending on cutting Need to add in corners, lintels, special shapes –5% waste

Rebar Waste comes from need to cut pieces to length –Rebar comes in lengths up to 40’ Overlap – 30 – 40 diameters at joints –Are you buying or bending pieces? –Storage area Mud, security, covered? will determine extra rebar needed –Caps, ties, shoes, etc – buy by the case

Steel No waste when doing steel quantities. –Beams and columns are fabricated to specs –Will have extra bolts, rivets

Wood 2x stock –Count all 2x stock as 8’ min pieces –5 – 10% extra for blocking, bad pieces Sheathing –Do not take out doors or windows when determining quantity –Add 5% waste Nails & screws –Buy by the 25 – 50 # box

Roof Tar paper, roll roofing –Want full sheets across roof if possible How many full sheets/ roll Shingles –Measure roof divide by 100sf gives # of squares –Add 10% waste Metal –Comes in sheets –Count full sheets needed

Other Exterior Siding –Figure square footage – excluding windows and doors –Add 5 – 10% waste Trim –5% waste

Interior Sheetrock –Want minimal seams 10% waste Plumbing –Buy pipe in 10’ lengths –Minimize joints – buy in contractor packs –5 – 10 % waste –Heating Air – minimal waste in large ducts Baseboard buy by length

Interior Electrical –Buy wire in boxes - 250’ lengths – charge by the box – 5% waste –Wire nuts – buy by the box Countertop –Linoleum – by the sheet –Granite, corian – cut to fit – no waste

Interior Trim –5 -20% waste depending on finish Flooring –Carpet & Linoleum Can have large waste factor depending on room size and carpet direction –Hardwood, tiles – 5%waste

Exact Counts Doors & Windows Plumbing Fixtures Appliances Sinks, toilets Light fixtures, vents, fans, outlets, switches cabinets