# Job Hazard Analysis: Block wall construction URL: https://hardhatbinder.com/en/jha/masonry/block-wall Last updated: 2026-10-23 Laying concrete masonry units (CMU, 8x8x16 block) with mortar, installing rebar, and grouting cells on a typical building wall. Covers material staging, mortar mixing, block cutting, laying from ground and frame scaffold, grouting, and cleanup. Outdoor work may include heat or cold exposure. > A general example for this task. Your JHA should reflect your crew, equipment and site — review it with a competent person before work starts. ## Steps, hazards and controls ### 1. Stage block, mortar, sand, and rebar near the wall - **Back and hand injuries from lifting 35-40 lb block and 80 lb mortar bags** (Medium): Have the supplier drop pallets close to the work with a forklift or boom truck.; Use a pallet jack, wheelbarrow, or block cart to move material.; Lift with your legs, keep the load close, and team-lift mortar bags over 50 lb.; Wear leather work gloves when handling block. - **Stacked block pallets tipping or falling** (Medium): Set pallets on firm, level ground; never stack more than two pallets high.; Keep loose block stacks no higher than 6 ft and step them back.; Stay out from under loads while the forklift or boom truck is unloading. ### 2. Set up the limited access zone and erect frame scaffold - **Workers struck by a wall collapse during construction** (High): Mark a limited access zone on the side without scaffold: as long as the wall and as wide as the wall height plus 4 ft.; Use caution tape or barricades and signs; only masons working on the wall may enter. - **Scaffold collapse or tip-over from poor base or missing parts** (High): Set frames on base plates and mudsills on firm, level ground; never use block or bricks to level.; Install all cross braces and pins; tie the scaffold in when height exceeds 4 times the base width.; Competent person inspects the scaffold before each shift and after any change.; Do not overload planks with block and mortar; keep loads within the rated capacity. ### 3. Mix mortar and grout in the mixer - **Caught in the rotating mixer paddles** (High): Keep the grate guard closed and in place while the mixer runs.; Never reach into the drum; shut off and unplug or remove the key before cleaning.; No loose sleeves, gloves near paddles, or hanging jewelry. - **Cement burns and eye injury from wet mortar and cement dust** (Medium): Open bags slowly and stand upwind of the mixer.; Keep clean water and an eyewash bottle at the mixer.; Wash wet mortar off skin right away; change mortar-soaked clothes.; Wear nitrile-coated gloves, safety glasses, and long sleeves. - **Gas mixer exhaust (carbon monoxide) and noise** (Medium): Run gas mixers outdoors only, away from openings; use electric mixers indoors.; Wear earplugs when working next to the running mixer. ### 4. Cut block with a masonry saw - **Silica dust from cutting block** (High): Plan layout to use half-block and bond beams and reduce cuts.; Use a stationary masonry saw with water running to the blade the whole cut.; For a handheld saw, use water feed; if cutting over 4 hours a shift, wear an N95 or better respirator.; Never dry cut or dry sweep dust. - **Cuts and kickback from the saw blade** (High): Keep the blade guard in place; check the blade for cracks and correct rating.; Feed block slowly on the saw cart; keep hands clear of the blade path.; Plug electric saws into a GFCI and keep cords out of water.; Wear a face shield over safety glasses and hearing protection. ### 5. Lay block courses and set rebar - **Impalement on exposed vertical rebar** (High): Bend over or cap every exposed rebar end with rebar caps or troughs.; Do not work above uncapped rebar. - **Falls from scaffold while laying upper courses** (High): Fully plank the work level and install guardrails on scaffold over 10 ft.; Climb using the built-in ladder or access frames, never the cross braces.; Keep planks clear of mortar drops and loose block to prevent trips. - **Unbraced wall blown over by wind** (High): Brace walls over 8 ft tall until grout cures and the wall is tied to the structure.; Stop work and clear the limited access zone in high winds. - **Heat illness during summer work** (Medium): Provide cool water and shade; drink a cup every 15-20 minutes.; Schedule heavy work early and give new workers time to get used to the heat.; Watch each other for dizziness, cramps, or confusion and report it right away. ### 6. Grout the cells - **Wet grout splash to eyes and skin** (Medium): Pour from a bucket or grout hopper at a controlled rate; do not overfill.; Wear safety glasses, nitrile-coated gloves, and long sleeves. - **Wall blowout or movement from grout pressure** (Medium): Grout in lifts per the plans and let mortar set before grouting.; Keep the limited access zone closed during grouting. ### 7. Clean up tools, site, and take down scaffold - **Silica dust from sweeping and cleaning** (Medium): Wet down debris or use a HEPA vacuum; no dry sweeping or compressed air. - **Trips and falls from debris and broken block** (Low): Pick up broken block and mortar drops daily and keep walkways clear. - **Falls or dropped parts while dismantling scaffold** (Medium): Dismantle from the top down under the competent person; lower parts by hand line, never throw them.; Keep the area below barricaded until takedown is complete. ## Required PPE - Hard hat — ANSI Z89.1, at all times on site. - Safety glasses — ANSI Z87.1 at all times; add a face shield when cutting block. - Gloves — Leather for handling block; nitrile-coated for mortar and grout. - Hearing protection — Earplugs or earmuffs when running the saw or near the gas mixer. - Respirator — N95 or better when handheld saw cutting exceeds 4 hours per shift. - Safety-toe boots — Waterproof safety-toe boots at all times. - Long sleeves and pants — To keep wet cement off your skin. ## Training - Scaffold user training; competent person for scaffold erection and inspection. - Silica hazards and the written exposure control plan. - Hazard communication for cement, mortar, and grout (read the SDS). - Safe operation of the masonry saw and mortar mixer. - Heat illness recognition and prevention. ## Emergency If a wall or scaffold collapses: stop all work, call 911, and give the site address. Do not move the injured person unless they are in further danger. Clear everyone from the collapse area, then give first aid until help arrives. For cement in eyes, flush with clean water for at least 15 minutes. ## Official sources - [29 CFR 1926.706](https://www.ecfr.gov/current/title-29/section-1926.706) — Requirements for masonry construction - [29 CFR 1926.701](https://www.ecfr.gov/current/title-29/section-1926.701) — Concrete and masonry — general requirements - [29 CFR 1926.451](https://www.ecfr.gov/current/title-29/section-1926.451) — Scaffolds — general requirements - [29 CFR 1926.1153](https://www.ecfr.gov/current/title-29/section-1926.1153) — Respirable crystalline silica - [29 CFR 1926.250](https://www.ecfr.gov/current/title-29/section-1926.250) — Materials storage - [29 CFR 1926.102](https://www.ecfr.gov/current/title-29/section-1926.102) — Eye and face protection - [29 CFR 1926.59](https://www.ecfr.gov/current/title-29/section-1926.59) — Hazard communication - [OSHA](https://www.osha.gov/heat-exposure) — Heat — hazard recognition and prevention --- Source: HardHat Binder, operated by Leadspire LLC. Templates to be reviewed by a competent person before use; not legal advice; not affiliated with OSHA.