# Lay bricks properly

*Mortar, setting out and bonding, taught with walls that build themselves on screen so you can see why the rules exist.*

## Production summary

- Modules to record: 2
- Total script: 1090 words, about 7 minutes of finished audio
- Voices: Amara (host) and Nadia (practice educator)
- Level: Beginner to competent DIY, and a grounding before formal training

## Accreditation wording that must appear in the description

- **The CPD Certification Service** (planned): Application scheduled.

> Do not upgrade any of these words in a description or a thumbnail. Aligned is not accredited, and planned is not approved.


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## Mortar: the part that decides whether the wall lasts

**Runtime** about 4 minutes. **Words** 547. **Starts at** 00:00 in the full course recording.

### Learning outcomes to state on camera

- Choose a mortar mix appropriate to the brick and the exposure
- Mix mortar to a consistent, workable and repeatable standard
- Explain why a stronger mix is usually a worse mix
- Handle materials safely, including the real risks of cement and silica

### Script


`[CUE 1]` *Two walls side by side: soft mortar cracking in the joint, hard mortar spalling the brick face.*

**AMARA**  [00:00]
I would have guessed that more cement means a stronger wall.

**NADIA**  [00:04]
Everybody does, and it is the most expensive mistake in domestic bricklaying. Mortar is supposed to be weaker than the brick.

**AMARA**  [00:12]
Weaker? Deliberately?

**NADIA**  [00:13]
Deliberately. Mortar is a sacrificial material. Every wall moves, with temperature and with moisture. You want that movement to crack the mortar joint, because a joint can be raked out and repointed by anybody for very little money.


`[CUE 2]` *Victorian wall with blown brick faces after hard repointing.*

**AMARA**  [00:28]
And if the mortar is stronger than the brick?

**NADIA**  [00:32]
Then the brick cracks instead. And now you are not repointing, you are cutting out and replacing bricks in a wall, which is a different job and a different bill.

**AMARA**  [00:44]
Is that why so many old houses look like the brick faces are falling off?

**NADIA**  [00:50]
Precisely why. Somebody repointed a soft Victorian handmade brick with a hard modern cement mortar. The wall could no longer move or breathe, moisture got trapped behind that hard pointing, it froze, and the face of the brick blew off. You can drive down any street and see it.


`[CUE 3]` *Bucket gauging beside shovel gauging, with the resulting colour banding.*

**AMARA**  [01:10]
So what mix do I use?

**NADIA**  [01:12]
For most external brickwork in ordinary exposure, one part cement, one lime, six sand. Softer or handmade bricks and older solid walls want one, two, nine, which is gentler still.

**AMARA**  [01:24]
And when do I go stronger?

**NADIA**  [01:26]
Where it gets wet and freezes. Below the damp proof course, freestanding garden walls, copings, parapets. There you want one, half, four and a half. Everywhere else, resist the urge.


`[CUE 4]` *Trowel drawn through mortar holding a peak, then too wet, then too dry.*

**AMARA**  [01:38]
What about sand? Sand is sand.

**NADIA**  [01:41]
It really is not. Use building sand, which people also call soft sand. Sharp sand is for concrete and screed, and if you lay bricks with it you will get a harsh gritty mortar that tears off the trowel and fights you all day.

**AMARA**  [01:58]
How do I get consistency between batches?

**NADIA**  [02:01]
Gauge by bucket, never by shovel. A shovel varies with who is holding it and how tired they are, and by four in the afternoon it is a different measure entirely. Same bucket, count it out.


`[CUE 5]` *Cement burn progression on skin over hours.*

**AMARA**  [02:16]
Why does that matter so much?

**NADIA**  [02:18]
Because a wall built from batches that varied will dry with visible colour banding across it. It looks like stripes and there is nothing you can do about it afterwards.

**AMARA**  [02:30]
How do I know it is the right wetness?

**NADIA**  [02:34]
Draw the trowel through it. It should hold a peak, cling to a vertical trowel face for a moment, then slide off cleanly. If it slumps flat it is too wet. If it tears and crumbles it is too dry.


`[CUE 6]` *Dry cutting dust cloud beside water suppressed cutting.*

**AMARA**  [02:50]
Last thing, and I want you to be blunt. What is the danger?

**NADIA**  [02:55]
Two, and both are underrated. Wet cement causes chemical burns, and because it is painless at first people kneel in it or let it sit inside a glove and end up in hospital with full thickness burns. Waterproof gloves, and wash it off immediately.

**AMARA**  [03:12]
And the second?

**NADIA**  [03:13]
Silica. Cutting bricks and blocks dry with a grinder throws out enormous quantities of respirable crystalline silica, and it causes silicosis and lung cancer. Water suppression or on tool extraction, and proper respiratory protection. It is the most serious long term risk in the entire trade and it is the one you will see ignored on almost every site you walk past.

### Sources for the on screen credit

- BS EN 1996 and PD 6697, mortar for masonry, British Standards Institution
- Cement and skin, and control of silica dust, Health and Safety Executive
- Brickwork good practice guides, Brick Development Association

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## Setting out and bonding: getting the first course right

**Runtime** about 4 minutes. **Words** 543. **Starts at** 03:38 in the full course recording.

### Learning outcomes to state on camera

- Set out a wall to gauge and explain why bricks are the sizes they are
- Lay a stretcher bond correctly, including the half bat at the ends
- Use a line, level, gauge rod and plumb correctly
- Recognise the common bonds and where each is used

### Script


`[CUE 1]` *Brick dimensions with the 10mm joint added, showing 225 and 215 resolving.*

**AMARA**  [03:38]
Why is a brick the size it is? It looks completely arbitrary.

**NADIA**  [03:43]
It looks arbitrary until you add the joint. A standard brick is 215 long, 102.5 wide, 65 high. Add a 10mm joint to the length and you get 225.

**AMARA**  [03:55]
And the width?

**NADIA**  [03:56]
Two widths plus a joint. 102.5, plus 102.5, plus 10, gives 215. Which is exactly the length of a brick.


`[CUE 2]` *Gauge rod against a wall with four courses to 300mm marked.*

**AMARA**  [04:04]
So a brick laid across the wall is the same length as one laid along it.

**NADIA**  [04:10]
That is the whole system. Without it, bonding is impossible. And the height does the same thing: 65 plus 10 is 75, so four courses rise 300mm exactly. That is your gauge, and it is the number you check against all day.

**AMARA**  [04:27]
Where do people go wrong?

**NADIA**  [04:29]
The first course, almost always, and nothing you do afterwards rescues it. If the bottom is out, you spend the rest of the wall cutting bricks and fudging joints to hide it, and it shows anyway.


`[CUE 3]` *Dry set out of a first course with the end gap being distributed.*

**AMARA**  [04:44]
So what do I do before I mix anything?

**NADIA**  [04:47]
Set it out dry. Lay the entire first course on the foundation with no mortar, leave 10mm gaps, and see where it lands.

**AMARA**  [04:56]
And if it does not come out even?

**NADIA**  [05:00]
Then you adjust the joint widths very slightly across the whole run. A millimetre here and there across twenty bricks is invisible. What you must not do is take up the whole error in one place and cut a horrible little slip of brick at the corner, because that is the first thing anyone's eye will land on for the next fifty years.


`[CUE 4]` *Ends built and racked back, string line running between them.*

**AMARA**  [05:25]
How do I keep a long wall straight?

**NADIA**  [05:28]
You do not try. Build the ends first, several courses high, racking them back so they step. Then run a string line between them at the top of each course and fill in between.

**AMARA**  [05:42]
That feels like more work.

**NADIA**  [05:44]
It is far less. Keeping two small stacks accurate is easy. Keeping thirty bricks in a line accurate by eye is not, and every professional on every site does it the first way.


`[CUE 5]` *Load path spreading sideways through a bonded wall, then running straight down a straight joint.*

**AMARA**  [05:57]
Tell me about the bond itself.

**NADIA**  [05:59]
Stretcher bond, which is what almost every modern outer skin is. Each course offset by half a brick, so every brick spans the joint below it.

**AMARA**  [06:10]
Why does the offset matter structurally?

**NADIA**  [06:12]
Because a load coming down spreads sideways into the bricks either side instead of running straight down one continuous vertical joint. Line those joints up and you have a straight joint, which is much weaker and looks wrong the instant anybody glances at it.


`[CUE 6]` *Four bonds side by side: stretcher, English, Flemish, English garden wall.*

**AMARA**  [06:30]
And how do I make the offset at the end of the wall?

**NADIA**  [06:35]
A half bat. A brick cut in half across its length, starting every other course. That is what produces the stagger, and it is the first cut most people ever make.

**AMARA**  [06:47]
Any other bonds I should know?

**NADIA**  [06:50]
Three worth recognising. English bond alternates whole courses of stretchers and headers, and it is very strong. Flemish alternates them within every course and it is the handsome one you see on Georgian houses. And English garden wall bond runs three or five stretcher courses to one header course, which uses fewer facing bricks. Which tells you exactly why it ended up on garden walls.

### Sources for the on screen credit

- Brickwork dimensions and bonding, Brick Development Association
- BS EN 771-1, specification for masonry units, British Standards Institution
- NVQ Level 2 Bricklaying, setting out, Construction Skills

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