Phonics, Spelling, & Grammar Resources

TTeaching the double consonant “ss” can be challenging for students as they learn when and why letters are doubled in English spelling.

The double consonant “ss” is not a standalone rule. Instead, it is best taught as part of broader spelling patterns, particularly the FLOSS rule and the final consonant doubling pattern.

Understanding how “ss” works helps students improve spelling accuracy and build confidence in reading and writing.

What is a Double Consonant?

A double consonant occurs when the same consonant appears twice in a row within a word (e.g. ss, ll, tt).

Double consonants are part of common spelling patterns in English and are often found in words with short vowel sounds.

Examples:

• pass
• kiss
• miss

When to Use the Double Consonant “ss”

1. The FLOSS Rule

The FLOSS rule explains when certain consonants are doubled at the end of one-syllable words.

If a word:

• has one syllable
• has a short vowel
• ends in f, l, s, or z

→ the final consonant is usually doubled.

Examples:

• kiss
• miss
• pass

👉 This is the key pattern for understanding “ss”.

2. Doubling “s” When Adding Suffixes

When a word already ends in ss, the double consonant is maintained when adding suffixes that begin with a vowel.

Examples:

• miss → missed, missing
• pass → passed, passing

👉 No additional doubling is needed — the pattern stays the same.

3. “ss” in Longer Words

Double “ss” also appears in many multisyllabic words.

Examples:

• lesson
• message
• classic

👉 These are best taught as recognised spelling patterns.

Important Clarification

Not all words ending in s use double ss.

Examples:

• bus
• gas
• this

👉 Doubling depends on the FLOSS pattern, not just the letter “s”.

Common Student Difficulties

Forgetting to Maintain Double “ss”

Students may write:

• mising instead of missing
• pased instead of passed

Overgeneralising Doubling

Students may incorrectly write:

• buss instead of bus
• gass instead of gas

Confusion with Similar Words

Students may confuse:

• desert and dessert

Difficulty Recognising Patterns

Words like lesson and message are often learned as familiar spelling patterns rather than through a rule.

Teaching Tips for Double Consonant “ss”

• Explicitly teach the FLOSS rule, including “s”
• Use word sorting activities (kiss, miss, pass)
• Model adding suffixes (miss → missing)
• Use word families (-iss, -ass, -oss)
• Reinforce through reading and spelling practice

Example Words for Teaching

• kiss
• miss
• pass
• missing
• passed
• lesson
• message
• classic

Why This Matters

Understanding how and when to use double consonants — including “ss” — helps students:

• recognise spelling patterns
• improve accuracy in writing

Strong spelling knowledge supports both reading fluency and written communication.

Final Thoughts on Teaching the Double Consonant “ss”

Understanding the double consonant “ss” helps students apply spelling patterns more accurately. Rather than teaching “ss” as a standalone rule, it is more effective to focus on the FLOSS pattern and the final consonant doubling pattern.

With clear modelling, repeated exposure, and targeted practice, students can develop confidence in recognising when doubling is required and when it is not.

To make teaching double consonants easier, explore our ready-to-use resources below to support your phonics lessons and reinforce student learning.