TuffSpec Ground Glue
A rapid set post compound that sets fence posts, gates and signs without water, mixing gear or a wheelbarrow. One pouch per post. An anti-shrink formula that grips the ground instead of sitting on it, exceeding concrete on uplift.
- Exceeds 2,200 lbs uplift on timber, round and steel posts
- 1.7 times denser than the next best post foam
- Does not shrink. No gap, no wobble.
- Grips steel like glue, where concrete shears off
- Tear tab built in. No scissors, no water, nothing to clean up.
The concrete alternative for setting posts. Join the list to get it first.
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Everything is in the bag. The two parts are sealed apart inside the pouch. You burst the seal, mix it in your hands, tear the corner and pour. Nothing to measure, nothing to add.
It goes in as a liquid and fills the hole. Then it sets hard without shrinking back, so it stays pressed against the ground it set into. The post is not sitting in the hole. It is glued to it.
Set in three minutes. Build on it in thirty.
- Type
- Two part expanding polyurethane
- Colour when cured
- Charcoal
- Density
- 7.5 lbs per cubic foot
- Uplift resistance
- Exceeds 2,200 lbs
- Mix time
- 15 seconds
- Set time
- 3 minutes
- Ready to build on
- 30 minutes
- Minimum hole depth
- One third of total post height
- Best used at
- 65 to 77°F
Reactive polyurethane system. Mixing causes rapid expansion and heat. Wear safety glasses and chemical resistant gloves. Use outdoors or in a well ventilated area. Read the pack before use. Safety Data Sheet at buildtuff.com.
Burst the seal, mix it over your knee for fifteen seconds, tear the tab, pour it in. Four steps, no water, no gear. The full walkthrough is further down the page.
One pack does most 4x4 posts in a 6 inch hole at any standard depth. The full table is further down the page.
Ships across the USA. Rates calculated at checkout.
Reactive polyurethane system. Mixing causes rapid expansion and heat. Wear safety glasses and chemical resistant gloves. Use outdoors or in a well ventilated area. Read the pack before use. Safety Data Sheet at buildtuff.com.
Any post you'd set in concrete, without the back-breaking work
Everything you need is in the bag
No water. No wheelbarrow. No mixer. Nothing to hose out at the end of the day, and nothing left over to get rid of.
Built to fix what post foam got wrong
 |
 |
|
|---|---|---|
| Material in the hole | 7.5 lbs per cubic foot | 3.5 |
| Shrinks as it dries | No | Yes, reported |
| Under load | Rigid. Does not flex. | Soft. Flexes with the post. |
| Grip on steel | Locks on hard and stays put | Bonds, but the foam gives |
| Colour in the ground | Charcoal, like concrete | Yellow |
| Build on it | 30 minutes | 2 hours |
And 1.7 times denser than the leading code-certified post anchor.
Fast 2K Post Anchor, 4.3 lbs per cubic foot, ICC-ES evaluation report ESR-4077.
Less than half the digging
Concrete holds by mass, so it needs a big hole. TuffSpec holds by pressure and grip, so a tighter hole gives it more to press against. Bigger = stronger is concrete thinking. TuffSpec flips it.
Same depth as concrete, half the width. Less digging means:
Concrete sits in the ground. TuffSpec locks into it.
Concrete sits in the hole as a separate lump. TuffSpec goes in as a liquid, runs into every ridge the auger left, then expands and presses out against the entire surface of the hole. It sets hard without shrinking, so the post, the glue and the soil become one thing — push the post and the load spreads down the full depth of the hole and out into the earth, instead of landing on one point.
We made a post foam that doesn't shrink
Three things had to be true at once. Any one of them alone would not hold a post.
How many you need
Square. Round. Steel. We tried to pull them all out.
Every post type, set in TuffSpec, winched straight up against concrete controls. Every TuffSpec timber post exceeded 2,200 lbs of uplift. On steel it wasn't close.
The winch wouldn't move it
Questions about TuffSpec
Because it holds a different way. Concrete needs weight, so it needs a big hole. TuffSpec grabs the dirt, so a tighter hole gives it more to hold onto.
At least a third of the post. Same as concrete. Only the width changes.
No. Shrinking is what made the old post foams fail. Ours sets against the dirt and stays there.
Yes, and it is one of the things it does best. Concrete sets around metal but does not stick to it. TuffSpec grabbed every metal post we tested.
In our testing it held longer every time. All seven concrete posts came out at or around 2,200 lbs. Every TuffSpec post went past that, and one could not be pulled with an excavator.
Charcoal grey. It looks like concrete in the ground, not bright yellow foam.
It will not reach full strength. Give it the full fifteen seconds over your knee. It is the one step worth slowing down for.
No. There is a tear tab built into the pack.
Clear it out first. Do not pour into standing water.
Cut the top back on a slope so water runs off away from the post instead of sitting against it.
Ground level and low level decks, yes. Not raised decks.
Built for the way you actually work
A smaller hole. Nothing to mix. Nothing heavy to carry. A post that is glued to the ground instead of sitting in it.
The concrete alternative for setting posts. Join the list to get it first.
Be first in line
The first run goes to this list.
No spam, just the launch.