How to Level a Floor with Screed (Step-by-Step, No Guesswork)

A floor that isn’t level will show up everywhere.

Tiles won’t sit right.Laminate feels uneven.And anything you install on top will highlight every dip and hump underneath.

Screeding fixes that — but only if it’s done properly.

👉 This is how to level a floor with screed the right way, based on what actually works on site.

Start With the Prep (This Is Where Most Jobs Fail)

Before you even think about mixing screed—

You need to get the surface right.

Remove High Spots and Loose Material

Go over the floor and knock off:

• High bumps

• Old adhesive ridges

• Loose debris

• Any flaky or weak areas

👉 If you leave high spots, they’ll show through the screed.

Clean the Floor Properly

Next step:

• Sweep thoroughly

• Vacuum the entire surface

👉 Get as much dust and debris off as possible.

Because screed will not bond properly to a dusty surface.

Apply a Bond Layer (Don’t Skip This)

You cannot just pour screed onto a bare floor.

It needs a bond.

If the surface is dusty:

Use a penetrating primer (like the one from Wickes)

👉 This locks everything down and stabilises the surface.

If the surface is clean and solid:

Use an SBR bonding agent

👉 Improves adhesion and helps the screed grip properly.

⚠️ Important:Always check the screed manufacturer’s instructions.

👉 Some screeds require their own specific primer system.

Using the wrong primer can lead to debonding later.

Let it dry fully (usually overnight).

Rush this and you risk failure.

Choose the Right Screed (Very Important)

Not all screeds are the same.

Using the wrong one will cause problems.

Timber Floors

If you’re going over timber—

👉 You must use a flexible screed

Timber moves.

Standard screed doesn’t.

👉 Use the wrong one and it will crack.

Solid Floors (Concrete / Existing Screed)

👉 Standard screed is usually fine.

Check Depth Limits on the Bag

Every screed has limits.

Some are:

• 1mm – 10mm

Others:

• 3mm – 40mm

👉 Always check.

If you go outside the limits:

• It can crack

• Fail

• Not cure properly

Buy the right screed for your job.

Set Your Level (The Most Important Step)

Place your laser level on the floor and set it to flooring mode.

You want a continuous laser line around the room.

If the line disappears—

👉 Raise the laser slightly until it’s visible everywhere.

Now:

• Mark that level with masking tape around the room

• Turn off the laser

👉 That’s your finished height.

Calculate How Much Screed You Need

Don’t guess.

Measure from the floor to your tape at multiple points.

Simple method:

1. Measure depth in several places

2. Add them together

3. Divide by number of readings = average depth

Example:

Average depth = 10mmRoom = 4m x 2.5m = 10m²

👉 Most screeds cover ~2m² per bag at 10mm

So:

10 ÷ 2 = 5 bags minimum

👉 If you’ve got dips — add more.

And always:

👉 Buy one extra bag — you can return it

Running out mid-pour is not an option.

Tools You’ll Need (Don’t Wing This)

• Large bucket

• Powerful drill + paddle mixer

• Spike roller

• Spike shoes

• Laser level (flooring type)

👉 Before you start:

Make sure your spike shoes are tight and secure

Loose spikes mid-job = ruined screed.

Block Off Areas First

Screed flows.

Control it.

Use timber (2x1 works well) to block:

• Doorways

• Under kitchen units

• Any areas you don’t want screed entering

Mixing the Screed (Be Precise)

Follow the bag exactly.

👉 Do NOT guess the water.

Too much:

• Weakens it

• Causes cracking

Too little:

• Won’t flow

• Hard to level

👉 Never add extra water “to make it easier” — it will cost you later.

Always mix in a clean bucket.

Old hardened bits will ruin your mix.

Working Time (Plan This Properly)

Most screeds give you:

👉 10–30 minutes working time

Once mixed—

You’re on the clock.

Don’t mix more than you can pour.

And don’t stop mid-job.

Pouring the Screed (Do This Properly)

Start at the furthest point from the door.

Work your way back.

Important:

👉 Don’t pour directly into corners

Start slightly away—

Then work it into edges with your roller.

Better control.

Cleaner finish.

As You Pour:

• Spread the screed

• Work into edges

• Use spike roller lightly

• Remove air bubbles

👉 Don’t overwork it — let it self-level.

Keep a Wet Edge

This is critical.

👉 Always pour into fresh screed

If one section dries before the next—

You’ll get ridges.

Work to Your Tape Line

That tape is your guide.

Hit it.

Don’t exceed it.

Expansion & Movement (Often Missed)

On larger areas—

Consider a small perimeter gap around edges.

👉 Screed expands and contracts as it cures

If it’s tight against walls—

It can crack.

Aftercare (Don’t Ruin It Now)

Once done:

• Leave it alone

• No foot traffic early

• No drafts blasting it

• No direct heat

👉 Uneven drying = cracking

Drying vs Ready for Flooring

Important distinction:

• Walkable ≠ fully cured

• Dry to touch ≠ ready for tiles

Some screeds:

• Walkable in 24 hours

• Need several days before flooring

👉 Always check the product data.

🔚 Final Thought

Screeding isn’t difficult—

But it’s precise.

You get:

• One mix

• One pour

• One chance

Get your prep right.

Choose the right screed.

Set your levels properly.

👉 And you’ll get a flat, professional finish.

Rush it—

And every mistake shows.

❓FAQ: Floor Screeding

How thick can you lay floor screed?

Depends on the product — some are 1–10mm, others 3–40mm. Always check the bag.

How long before you can walk on screed?

Often around 24 hours — but check the product.

Why is my screed cracking?

Usually:

• Too much water

• Wrong product. did you need flexible?

• No primer

• Too Fast drying

• Movement underneath

Can you screed over timber floors?

Yes — but you must use a flexible screed.

How long before flooring can go down?

Varies — often several days. Always follow manufacturer guidance.