By Colin FosterUpdated November 2026
Building a fire pit from cinder blocks for a fire pit project is one of the most practical backyard upgrades a homeowner can take on. Cinder blocks are inexpensive in the sense that they are widely sold, easy to stack, and forgiving for a first-time builder. But not every product sold under the cinder block umbrella belongs in a fire ring, and some items that look similar are meant for play, not heat. This guide focuses on what matters when you choose materials for a block-built fire pit: heat tolerance, stability, size, and how the pit will be used. We compared three products that people often look at when researching this project, using manufacturer listings, specifications and common owner feedback patterns as our basis. We did not test them ourselves.
Our top picks at a glance
- 1
TOP CHOICEBest overallTWS 10 Compressed Hardwood Fuel Blocks 10-Pack – 100% Natural Sawdust Fire LogsView on Amazon - 2
Best for fuel on a budget100% Natural Compressed Sawdust, Long Burn and High Heat Hardwood Fuel Blocks (3 Pack)View on Amazon - 3
Best for kids' build-and-learn playKaplan Early Learning Company Foam Cinder Block Builders – Set of 20View on Amazon
Our Top Picks
| Product | Best for | Key feature |
|---|---|---|
| TWS 10 Compressed Hardwood Fuel Blocks 10-Pack | Burning fuel inside a block fire pit | Compressed natural sawdust fuel with long burn time |
| 100% Natural Compressed Sawdust Hardwood Fuel Blocks (3 Pack) | Occasional backyard fires on a smaller budget | Small, low-commitment pack size |
| Kaplan Early Learning Foam Cinder Block Builders – Set of 20 | Kids’ play and stacking practice near a yard | Lightweight foam blocks, not for heat |
TWS 10 Compressed Hardwood Fuel Blocks 10-Pack – 100% Natural Sawdust Fire Logs
TWS 10 Compressed Hardwood Fuel Blocks 10-Pack – 100% Natural Sawdust Fire Logs, Long Burn High Heat, Low Ash Eco-Friendly for Fireplace Wood Stove Fire Pit (10 Blocks)
Best for: Burning fuel inside a block fire pit
This is the fuel that goes into a finished cinder block fire pit, not a building material. It suits homeowners who have already stacked their blocks and want a clean, consistent fire source. Owners of compressed sawdust fuel products frequently mention easier starting and less smoke than loose firewood.
Key specs
- Pack of 10 blocks
- 100% natural compressed sawdust
- Listed for fireplaces, wood stoves and fire pits
Pros
- Long burn time per block, as listed
- Low ash output compared with some loose wood
- Consistent sizing that stacks neatly in a pit
Cons
- Not a building material, so it does nothing for the pit structure
- Requires dry storage to keep blocks from absorbing moisture
Bottom line: A strong pick for homeowners who already have a cinder block ring and want a dependable fuel source.
100% Natural Compressed Sawdust, Long Burn and High Heat Hardwood Fuel Blocks (3 Pack)
100% Natural Compressed Sawdust, Long Burn & High Heat for Fireplaces, Stoves & Fire Pits, By Bio-Diversity Envi Hardwood Fuel Blocks (3 Pack)
Best for: Occasional backyard fires on a smaller budget
A smaller pack makes sense for someone trying a block fire pit for the first few seasons before committing to bulk fuel. It is also useful as a test for how a particular pit draws and burns.
Key specs
- Pack of 3 compressed fuel blocks
- 100% natural compressed sawdust
- Marketed for fireplaces, stoves and fire pits
Pros
- Low commitment for trying a new pit
- Same compressed format as larger packs
- Easy to store in a garage or shed
Cons
- Runs out quickly if the fire pit is used often
- Fewer blocks per purchase means more frequent reordering
Bottom line: Best for households that burn a few times a season and want to keep fuel storage small.
Kaplan Early Learning Company Foam Cinder Block Builders – Set of 20
Kaplan Early Learning Company Foam Cinder Block Builders – Set of 20
Best for: Kids’ build-and-learn play near the yard
This set is a children’s toy made of lightweight foam, not a material for a fire pit. It belongs in this list only because families looking for “cinder blocks” sometimes find it while planning a yard. It is useful for kids who want to stack and build, and it should be kept well away from any fire.
Key specs
- Set of 20 foam blocks
- Designed for children’s building and stacking play
Pros
- Lightweight and easy for small hands to move
- Soft edges suited to play
- Good for early stacking and counting activities
Cons
- Not heat resistant and not suitable for any fire ring
- Does not provide structural strength for outdoor use
Bottom line: Choose this only for children’s play. Do not use it to build or line a fire pit.
Buying Guide
Heat resistance and material type
Standard concrete or cinder blocks are the usual choice for a fire ring because they tolerate heat without releasing harmful fumes when used properly. Foam, plastic and most decorative resin blocks are not made for direct flame. Check the material listing before buying any block for a pit.
Good picks for this: TWS 10 Compressed Hardwood Fuel Blocks 10-Pack (fuel, not structure); Kaplan Early Learning Foam Cinder Block Builders (play only)
Block size and wall height
A common block measures 8 by 8 by 16 inches. Stacking two to three courses gives a usable wall height of roughly 16 to 24 inches, which is a comfortable seating height for most backyard fires. Plan your ring diameter so the inside opening is comfortable for the fire and safe for people seated around it.
Good picks for this: 100% Natural Compressed Sawdust Hardwood Fuel Blocks (3 Pack) for sizing a small test fire
Stability and level base
Even a well-chosen block will tip or shift if the base is uneven. Dig out the site, add compacted gravel, and check level with each course. Use construction adhesive or mortar only if the manufacturer of your chosen block allows it.
Good picks for this: TWS 10 Compressed Hardwood Fuel Blocks 10-Pack once the base and stack are finished
Fuel compatibility
Compressed fuel blocks burn more evenly and with less smoke than many loose logs, and they suit a contained block pit well. Only burn fuel products labeled for fire pits or fireplaces, and never burn treated lumber, painted wood or trash.
Good picks for this: TWS 10 Compressed Hardwood Fuel Blocks 10-Pack; 100% Natural Compressed Sawdust Hardwood Fuel Blocks (3 Pack)
Durability and weather exposure
Concrete blocks handle rain and sun well, but freeze-thaw cycles can crack blocks over time if water sits in the pores. Keep the top course covered when the pit is not in use and inspect for cracks each spring.
Good picks for this: TWS 10 Compressed Hardwood Fuel Blocks 10-Pack (store dry to prevent moisture absorption)
Safety clearance and placement
Keep the fire pit at least 10 to 25 feet from structures, fences and overhanging branches, and check local burn rules. Use a metal mesh screen if sparks are a concern. Never leave a fire unattended, and keep a water source or extinguisher nearby.
Good picks for this: Kaplan Early Learning Foam Cinder Block Builders, which should always be kept away from any fire area
Use case and family needs
If the pit is mainly for adults on weekends, a larger ring and steady fuel supply make more sense. If children play nearby, consider a lower wall height and clear rules about the fire area. Foam building sets can serve as a separate play activity, not part of the fire feature.
Good picks for this: Kaplan Early Learning Foam Cinder Block Builders for kids’ play; TWS 10 Compressed Hardwood Fuel Blocks 10-Pack for regular adult use
FAQ
Can I use regular cinder blocks for a fire pit?
Yes, standard concrete or cinder blocks are commonly used for backyard fire rings. Choose solid, undamaged blocks and avoid any with cracks or crumbling edges, since those can fail under heat.
Are cinder blocks safe to burn near?
Cinder blocks are non-combustible and handle the heat of a typical backyard fire. Keep the fire itself contained and maintain safe clearance from structures and vegetation.
Do I need mortar to stack cinder blocks for a fire pit?
Many builders stack blocks dry because the fire pit is not a load-bearing structure. Mortar or construction adhesive can add stability, but confirm that the product you choose allows it and that the mortar is rated for heat.
What size fire pit should I build with cinder blocks?
A common approach is an inside diameter of about 24 to 36 inches with two to three courses of standard blocks. Adjust for the number of people you expect to seat around the fire.
Can I burn firewood in a cinder block fire pit?
Yes, dry, seasoned firewood is the most common fuel. Compressed fuel blocks are an alternative for cleaner, more consistent burns. Never burn treated lumber, painted wood, or household trash.
How do I keep cinder blocks from cracking over time?
Keep blocks dry when not in use, cover the top course, and inspect for cracks after winter. Replace any block that is split or crumbling.
Is foam cinder block play set useful for a fire pit project?
Foam play blocks are not heat resistant and cannot be used to build a fire ring. They are better suited to children’s stacking activities away from the fire area.
Conclusion
For building and running a cinder block fire pit, the most useful items are solid masonry blocks for the structure and dry, labeled compressed fuel for the fire itself. Among the products reviewed here, the TWS 10 Compressed Hardwood Fuel Blocks 10-Pack suits homeowners who want a steady fuel supply. The 3-pack option suits those who burn only occasionally. The Kaplan foam block set belongs in a kids’ play area, not near a fire. Check local burn regulations, keep clearance around the pit, and always supervise fires.
Sources
- Consumer safety guidance on outdoor fire and heating equipment (cpsc.gov)
- Fire prevention and outdoor fire safety resources (usfa.fema.gov)
- Information on wood burning, smoke and clean-burning practices (epa.gov)
Related reading
- Fire Pit Using Cinder Blocks: 3 Best Picks for Backyards (2026)
- Concrete Blocks for Fire Pit: A Step-by-Step Build Guide for Beginners
- 6 Best Fire Pits with Cement Blocks for Backyards (2026)
- 6 Best Breeze Block Fire Pit Inserts and Wind Guards for Backyards
- Top 7 Movable Gas Fire Pit Options for Patios and Backyards (2026)
- Top 7 Gas Backyard Fire Pit Picks for Patios and Decks in 2026
About Colin Foster
Colin Foster is part of our editorial team and reviews and edits our backyard living & play guides, checking product details against manufacturer specifications and owner feedback.
