Register your business

Home / Advice / What are frogged bricks, and which way up do they go?

What are frogged bricks, and which way up do they go?

A frogged brick has a shallow hollow, called a frog, pressed into one or both of its largest faces. Many bricklayers lay them frog up so the hollow fills with mortar, but the brick maker's guidance and the job's design come first, so ask before work starts.

Last reviewed:

By the QuoteZila editorial team. Editorial policy.

What is a frog in a brick?

A frog is the shallow hollow pressed into one face of a brick. You see it on the large top or bottom face, not on the ends or the long sides that show in a wall. A brick with one frog is "single frogged". Some bricks have a frog on both faces.

The frog has a few jobs. It saves some clay and weight. It gives the mortar a pocket to grip. On many bricks it is where the maker stamps a name, so old bricks pulled from a demolished wall can sometimes be traced back to a works.

You won't see the frog once the wall is built, because it faces up or down into a mortar joint. What you do see is the face of the brick. Brickwork patterns, or bonds, are made by showing the long side of a brick, called a stretcher, or its short end, called a header [S1]. The frog plays no part in that pattern.

QuoteZila starts in Cheshire, with Crewe, Nantwich and Sandbach first, and anyone in the UK can post a brickwork job.

How do frogged, solid and perforated bricks differ?

There are three common shapes inside a standard-sized brick:

  • Solid bricks have no hollow at all. They are often used where both large faces might be seen, or where a design calls for them.
  • Frogged bricks have the shallow pocket on one or both faces.
  • Perforated bricks have holes running right through them, top to bottom, instead of a frog.

None of these is simply "better". The right brick depends on where it goes: an outer wall, a garden wall, the top course of a wall, below ground, or a repair to old brickwork. Your bricklayer or builders' merchant can explain which suits each place.

Which way up should a frogged brick go?

The usual answer is frog up. Laid that way, the bricklayer fills the hollow with mortar as they spread the bed for the next course, so the wall ends up solid, with no air pockets inside the joint.

Laying frog down is quicker, because the hollow doesn't need filling. But it can leave voids inside the wall unless the bricklayer takes care. Some brick makers and engineers give their own instructions for a particular brick or wall, and those come first.

If you're paying for the work, you can simply ask: "Which way will you lay the frogs, and will they be filled?" A good bricklayer will have a clear answer.

Why does the brick choice matter on an extension or repair?

On an extension, matching the old brickwork is often about planning as well as looks. The Planning Portal says that under the permitted development rules for extensions, the materials used in any exterior work must be of a similar appearance to those on the outside of the existing house [S2]. Frogs don't show, but the brick face, colour and size do.

On a repair, the brick needs to fit the size of the old ones and sit well with the wall around it. The Planning Portal also explains that many walls are cavity walls, with two skins of masonry tied together, and that where 25 per cent or more of the outer leaf of a wall is rebuilt, the building regulations would normally apply [S3]. A small patch repair is very different from rebuilding a whole wall. Ask the builder which applies to your job.

For repairs to mortar joints rather than bricks, repointing brickwork covers the job. If brick faces are flaking, brick spalling explains the common causes.

What should you ask a bricklayer?

Before work starts, these questions help you compare quotes:

  • Which bricks will you use, and do they suit this wall and this exposure?
  • Will frogged bricks be laid frog up and filled?
  • Who supplies the bricks, and is waste and leftover stock included?
  • Will the new brickwork match the old in size, colour and bond?
  • What mortar mix will you use, and will the joints match?

Citizens Advice says a quote is a fixed price, while an estimate is just a rough guess, and suggests getting written quotes from at least 3 different traders [S4]. Our builders page covers the trade more widely, and the brick cost guide explains what changes the price of the bricks themselves.

Jobs you might post

These are examples, not taken from real job posts.

  • "Garden wall about knee height has a cracked section. Looking for a bricklayer to rebuild it with matching bricks."
  • "Small single-storey extension. Need a bricklayer to quote for the outer skin, matching the house bricks as closely as possible."
  • "Old reclaimed bricks stacked in the garden. Want a low wall built from them. Please say if they are suitable."

A photo of the wall and the bricks around it helps a bricklayer price the job. Your job goes to up to five matched local businesses [QZ2]. QuoteZila is free for customers and local businesses [QZ1].

Honest status: QuoteZila is new. We're starting in Cheshire, beginning with Crewe, Nantwich and Sandbach, and growing area by area. Anyone in the UK can still post a job or register a business. How fast you get quotes depends on how many local businesses have joined near you. Businesses can register and receive jobs straight away. We don't check insurance, qualifications or registrations, so please check these yourself before you hire.

Posting a job is not open yet

Questions about frogged bricks

Why do some bricks have a hollow in them?

The hollow, called a frog, is pressed into the brick when it is made. It makes the brick a little lighter, gives the mortar something to key into, and on many bricks it carries the maker's name or mark.

Should frogged bricks go frog up or frog down?

Many bricklayers lay them frog up, so the hollow is filled with mortar and the wall is solid. Some designs and some brick makers say otherwise, so ask the bricklayer which way they will lay them and why.

Can I use frogged bricks for a garden wall?

Usually, as long as the brick suits being outside and exposed to weather. Ask the supplier or bricklayer which bricks suit a free-standing wall, and which bricks they would use for the top course.

Does QuoteZila check bricklayers?

No. We don't check insurance, qualifications or registrations, so please check these yourself before you hire. You can report a quote or a business from your job page.

This page is general information, not professional or legal advice. QuoteZila does not check Gas Safe, WaterSafe, NFRC, NICEIC or other registrations against the register on your behalf: look them up yourself.

Part of Advice. All services

Related trades

Cost guides

Related pages

Sources

  1. QZ1: QuoteZila product fact. QuoteZila home and FAQ copy.
  2. QZ2: QuoteZila product fact. QuoteZila FAQ How does getting quotes work.
  3. S1: Brick Bonds, Nottinghamshire Historic Environment Record (Nottinghamshire County Council). Accessed 2026-11-02. https://her.nottinghamshire.gov.uk/whats-new/brick-bonds
  4. S2: Extensions: planning permission, Planning Portal. Accessed 2026-11-02. https://www.planningportal.co.uk/permission/common-projects/extensions/planning-permission/
  5. S3: Is building regulations approval needed for work to external walls?, Planning Portal. Accessed 2026-11-02. https://www.planningportal.co.uk/permission/common-projects/external-walls/building-regulations/
  6. S4: Before you get building work done, Citizens Advice. Accessed 2026-11-02. https://www.citizensadvice.org.uk/consumer/getting-home-improvements-done/before-you-get-building-work-done/