Anchoring a gazebo or other outdoor structure like an arbor or pergola to a concrete base without drilling holes is a tricky but very handy skill. Once you've got it down, you can easily apply it to myriad smaller projects, such as anchoring a new house for your four-legged best friend, securing an outdoor kitchen, or erecting a patio entertainment area—the sky's the limit.
Safety Warning: To protect your skin, always wear protective gloves when you're working with masonry and glue. It's also a good idea to a equip a respirator and make sure you have adequate ventilation. Keep glue or other construction adhesives well out of the reach of children and animals, and try not to touch your face while you're working with these materials. Follow all manufacturer's guidelines for product use and safety.
Even though you won't need a drill or drill bits for this project, you'll still have to round up a few specific tools. Concrete is quite hard, obviously, and it requires masonry bits and a hammer drill to cut for bolt holes. None of the drill bits you would normally use for drilling into wood are strong enough for concrete, and they'll quickly become dull if used in that manner for more than a moment.
Gluing Bricks to Concrete
While the concept of gluing bricks or cinder blocks to concrete almost seems to defy logic, there are a number of name brand masonry adhesives on the market.
To begin, clean the surfaces to be glued as much as possible to ensure the best possible bond. Making sure that the temperature is optimal for the adhesive is also crucial—if it's too hot or too cold, the glue is not likely going to work properly. Typically construction adhesives work best at a temperature range between 69 and 95 degrees Fahrenheit, but check the product instructions to be sure. If the weather is too extreme, you might have to pitch a tent over the site and use heaters or coolers to bring the temperature into a viable range. Alternatively, you might be able to find a different brand of adhesive that will work in those conditions.
Apply the adhesive to the brick or cinder block to be glued, then carefully align them before setting the bricks in place so as not to smear the glue too badly, or end up with the bricks out of alignment when the adhesive is set up. Allow the glue to dry for at least 24 hours unless otherwise indicated by the manufacturer's instructions.
Gluing Wood to Concrete
To glue a piece of wood to concrete you'll again need to clean and dry the materials being glued together or the adhesive won't bond well, if it bonds at all. The lumber you're gluing to the concrete should be as flat and smooth as possible. If the wood is bowed or rough it can cause problems with bonding. This could lead to your gazebo coming loose under stress from wind and weather and winding up in a neighbor's yard, potentially causing serious damage and injury, for which you may be liable.
If you don't mind making holes in your concrete, you can use nails made specifically for nailing wood to concrete. Ask your local home improvement store sales clerk to help you locate concrete nails if that's your plan.
If it's not, your best option may be an epoxy glue made specifically for attaching wood to concrete. Many construction adhesives can do the trick.
Once the wood has been glued to the concrete, employ a brace or clamp to keep it in place until the glue dries completely. If this isn't practical, placing a weight on the wood will do just as well in place of a clamp. Don't move or remove the weight until the glue has dried completely.
Never assume that gluing bricks, wood, or any other materials to concrete for the purpose of securing a large structure like a gazebo will perform exactly like concrete anchors that do have to be drilled. Side torsion from wind and weather can eventually break the bond and leave your gazebo exposed to severe wind damage. Holes in concrete can always be filled in later with a little bit of cement patch or an epoxy resin.