In brief
- Screeding failures usually start before the screed is mixed, at a base that was not cleaned, damped, levelled or signed off.
- A supervisor closes the gap with dated hold points: base inspection, thickness and level checks, and written curing instructions.
- Ask for the mix ratio, the batch record and the level readings, and compare them with the project specification before the pour starts.
Contents
Floor screeding supervision gaps in Borama show up as uneven finished levels, hollow patches and cracks that appear weeks after the floor looks finished. The cause is usually not the trowel. It is that no one checked the base, the thickness, the mix and the curing while the work was still open.
Screed is the thin layer that gives a floor its final level and a surface for tiles, vinyl or carpet. It sits on a structural slab or a hardcore base and it follows whatever shape it is laid on. That is why supervision in the hours before and after the pour decides whether the floor is usable. A mix that dries before it sets cannot be trowelled flat, so confirm the day's temperature, wind and shade on site and adjust the curing method to match.
What does weak supervision let through before the screed goes down?
The base is the first thing supervision should check, because a screed cannot correct a slab that is already out of level or covered in dust.
The steps that need a sign-off before mixing are short and cheap. Clear the area of mortar droppings, sand and sawdust. Check that the slab or base is sound, with no loose material or soft spots. Damp the base so it does not pull water out of the mix, without leaving standing water. Set level pins, screed rails or a datum line so the crew has a visible target thickness. Agree the finished level with door thresholds, drainage falls and any tile bed in mind. Confirm that services running in the floor are fixed and protected before they are buried.
When no one owns these checks, the crew works to what looks right. Thick patches shrink, thin patches crack, and the fall to a wet area can end up running the wrong way. Ask the site supervisor for the inspection record for the base. If there is none, ask when the base was inspected and by whom.
How do uneven finished levels survive a floor check?
Uneven levels survive because the check happens after the screed has set, when correcting them means breaking out sound material.
A level check is quick with a straight edge, a spirit level and a tape, and it should happen while the screed is still workable. General practice is to check the surface with a straight edge laid across the floor and to keep the deviation within the tolerance the project specification sets. The same specification should state the design thickness of the screed, and the crew should confirm that thickness against the datum at several points, not just at the door.
Cracks, curling edges and hollow sounds under a tapped surface point to a mix or curing problem, not just a levelling problem. A screed mixed too dry, or one that lost its water to a dry base, can set weak and dusty. Water added later to make it workable can weaken it further. Ask for the mix ratio used and where it came from. The project specification or the engineer should confirm the ratio, the thickness and the tolerance before work starts.
Who should sign the hold points on a screed job?
Hold points work when one named person has to sign before the next step, and the client knows that person's name.
A simple sequence for a screed job is: base inspected and cleaned, datum and thickness agreed, mix and materials checked, screed laid and levelled, curing started, final level and finish accepted. Each step needs a signature and a date on one sheet. The site supervisor can hold the first four. The client or the client's representative should hold the final acceptance, and a structural or finishing engineer can be asked to confirm the specification items.
Check with the local authority which permits or inspections apply to the plot, and ask the project engineer to put the tolerance, thickness and curing method in writing. If a disagreement about a defect is likely, ask a laboratory or testing service about its rate and method for a level or strength check before work starts. Do not rely on a verbal instruction for any of these points. Read the contract's defect-notification and dispute clause now so you know the steps to follow if a defect appears later.
What to do next
For the next screed pour on the project, write a one-page hold point sheet with the base inspection, the datum and thickness, the mix ratio, the curing method and the final level check. Name the person who signs each line. Walk the base with the crew, take dated photographs, and file the signed sheet with the contract documents.
Frequently asked questions
How thick should a floor screed be in Borama?
Design thickness depends on the screed type, the base and the finish above it. General practice is to keep it within the thickness the project specification or engineer states, and to confirm that figure before mixing. A thin decorative topping and a bonded screed over a weak slab do not take the same thickness.
What causes hollow patches under a screed?
A dusty or dry base, a weak mix, or a screed laid too dry can all leave the layer unbonded, so it sounds hollow when tapped. The check is to tap the surface and to compare the mix and base preparation against the specification, ideally while the work is still open.
Can a screed fix an unlevel slab?
Only within the thickness the specification allows. A screed follows the base, so a slab that is badly out of level needs correction at the slab, not a thicker topping. Set the datum, measure the base and agree the correction method with the engineer first.
Local reporting: this article is written for building work in Borama and Somaliland. Ground conditions, prices and rules differ between places; confirm the details for your own site.