Frequently Asked Questions

1. How to Hire a Contractor
2. Aggregate Base: the Foundation
3. Aggregate Base: How deep?
4. Aggregate & Geo-Textile Fabric
5. What is Hot Mix Asphalt?
6. Driveway Sealing
7. Re-capping an old driveway
8. When is the best time to pave?
9. Steps in Driveway Construction
10. How long before I can drive on it?
11. How long will my new drive last?
12. Territory served?
13. Why chamfered edges on drive?
14. Why choose Trenton Paving?

1. How to Hire a Contractor

All reputable contractors will provide references. Ask references about contractor's quality of work, communication, attention to detail and cleanliness, on-time and on-budget performance, and final finish of the drive. Were there unpleasant surprises?

Specific considerations in reviewing bids:

Homeowners' three most common problems with contractors were:

Complaints and disappointments originate in lack of good project definition and inadequate communication; failure is a result of poor and rushed planning.

Our goal is Quality Workmanship leading to the highest levels of Client Satisfaction. We recognize that our reputation for good work at a fair price depends upon satisfied customers. Accordingly, we welcome your questions about how to best build your new driveway before and during installation.

2. Aggregate Base: the Foundation

The aggregate beneath the asphalt mat is the structure's foundation. Just as your house has aggregate beneath its footings, your driveway requires a base of packed stone. The aggregate serves two purposes. First, because it does not retain water, it acts as a frost barrier beneath the layer of asphalt avoiding heaving and casting of the asphalt surface in winter. Second, the packed aggregate base provides a stable layer aiding the asphalt mat support the design load.

Depth of aggregate bases and of asphalt mats will vary depending on (a) the intended use and loads of the driveway and (b) type of sub-soils beneath the drive.

The base of aggregate should be placed in layers not exceeding 6 inches depth to achieve adequate compaction. If 8 or 10 inches of compacted aggregate are required, the base should be built up in multiple layers. Adequate compaction of the aggregate is necessary to carry design loads. This level of compaction is achieved using large 3 Ton vibratory rollers and specially-designed plate packers for residential drives.

It is often advisable after installing 8 to 10 inches of aggregate to allow an additional 4 to 6 weeks for further settlement of the aggregate base before returning to pave. After this 'resting' period, the surface is given a final preparation and re-rolled, then paved.

3. Aggregate Base: How deep?

Please view the cut-away picture on the right side of your page.  It demonstrates inadequate aggregate base (crushed limestone gravel) placed on soil that appears to contain clay--an unacceptable construction technique. 

The base of aggregate (crushed limestone) works with the asphalt layer(s) to support loads (cars and trucks) on the driveway. The driveway will be designed according to the anticipated load --cars & pickups require less gravel base and asphalt thickness versus dump trucks and heavy equipment that require up to 450 mm of base gravel and two coats of asphalt. That said, a residential driveway laid on stable sub-soil requires only 150 to 250 mm (6" to 10") of crushed limestone aggregate. The new top layer, the last 100 mm, of limestone gravel should be 16 mm and finer limestone for best levelling prior to paving.

If the sub-soil contains rocks, clay and organics, deeper excavation is warranted. Clay and organic substances by their nature retain water. In winter the excess water in the sub-soil will freeze and expand, causing the asphalt mat riding on it to flex excessively and eventually crack. Rocks will work upwards with frost, eventually popping through the driveway surface. In summer, the presence of poor sub-soils is like a sponge absorbing and releasing water and kneading like dough, again causing the asphalt mat to rise and fall, eventually cracking. Once small cracks develop, the process accelerates with surface water able to enter the compromised area.

To avoid premature cracking on poor sub-soils, we routinely remove 200 to 300 mm (8 to 12 inches) of sub-soil and replace with 3" aggregate base, then install 16 mm (5/8") top layer of crushed limestone aggregate to level of 'bottom of asphalt'. This extra thickness over any remaining soft sub-soil improves the frost barrier and provides the strength to carry design loads for residential driveways. At times we will recommend geo-textile fabrics (see below)

 

4. Aggregate & Geo-Textile Fabric

Geo-Textile Fabrics are a relatively new development used as a barrier to combat inferior sub-soils containing clay.  Even when driveways are excavated to 8 and 10 inches, if clay is present in the sub-soil, it will slowly infiltrate the new aggregate base.  Once the clay has infiltrated the aggregate base, the ability of the aggregate to drain water is compromised.  The clay-impregnated aggregate now holds water, freezing and expanding in winter while shrinking and swelling in summer as water tables vary.  The presence of water in the clay results in premature cracking and damage.   The photo to the right is typical of the resulting premature asphalt damage--alligator cracks with rutted and heaved areas.

Geo-textile fabric is a heavy duty synthetic non-woven fabric costing about $1.00 per square meter.  It provides a cost effective barrier to clay infiltration.  The synthetic fiber will not rot in the soil and provides years of functionality.  The non-woven fabric 'filters', allowing water to drain downwards and preventing clay particles from migrating upwards into the aggregate foundation, thereby protecting the asphalt from heaving and collapsing. 

Geo-textile fabric is placed at the bottom of the excavation, then back-filled with aggregate in the traditional manner, layer upon layer with rounds of compaction, followed by final grading and laying of the asphalt mat.  Its presence prevents infiltration by damaging clay particles.

5. What is Hot Mix Asphalt?

Hot Mix Asphalt is an engineered mixture of stone and sand, "aggregate", coated in a petroleum tar, "asphalt cement".  Different sizes and proportions of aggregate are specified for specific applications--highway, parking lot or residential.  Similarly, there are different grades of asphalt cement suited for the moderate temperatures along the north edge of Lake Ontario, or cooler temperatures north of Highway #7, or "super highway cements" used on major highways.  

The desired mixture of aggregate is heated to approximately 150 degrees Centigrade and then tumbled with liquified asphalt cement to create Hot Mix Asphalt.  The Mix is then weighed into a dump truck and delivered to the job site, transferred to the paving machine and the mat laid on the previously prepared foundation of levelled and compacted crushed limestone. 

What are the Advantages of Hot Mix Asphalt?
Hot Mix Asphalt is strong and durable. Well constructed drives last 15, 20 or more years with minimal maintenance.
Hot Mix flexes unlike more rigid materials, allowing well-constructed drives to withstand freezing and thawing damage.
Hot Mix Asphalt is not damaged by winter salt and quickly warms in the sun to melt icy patches.
Hot Mix Asphalt is the most cost-effective solution available

6. Driveway Sealing

If installed correctly, a Hot Mix Asphalt driveway will provide 15, 20 or more years of service. However, the asphalt requires maintenance. Most importantly: caulk any cracks that develop to prevent water from permeating into aggregate and freezing - thawing.

If sealing your drive, new pavement should be allowed 90 days curing before a sealer is applied. Recommended temperature for application of sealer is above 10 degrees Centigrade over night; cooler temperatures are detrimental to finish.

Hot Mix Asphalt is best sealed with a petroleum-based sealer in a water emulsion, not a less expensive latex coating. A high-grade asphalt emulsion sealer can be applied every two to five years depending on climate, shade and wear patterns. We do not offer a sealing service but there are reputable installers in most municipalities.

7. Re-capping an old driveway

Re-capping -- an overlay of 38 mm (1.5 inches) of Hot Mix Asphalt -- provides excellent results for low cost on existing asphalt or concrete drives.  If the current drive is structurally sound -- no evidence of ruts and lumps -- re-capping may work to renew curb appeal.  Any weak spots are patched first, then the new coat applied on the existing drive. 

Excavation, and cost, is kept to a minimum by saw cutting and excavating 1 to 2 meter(s) at each end of the drive where asphalt must meet existing elevations of garage sills and roadway. 

Re-capping will NOT provide a long-lasting solution if the sub-soil was not correctly excavated before the original drive was laid.  Poor sub-soil conditions are evidenced by ruts and ridges in the asphalt surface.  Simply leveling these defects before re-capping omits necessary removal of soft sub-soil and its replacement with crushed limestone, properly compacted to form a solid foundation for the new asphalt mat.

8. When is the best time to pave?

Air and surface temperature with asphalt mat thickness are vital in determining the time available for compaction. If the asphalt mat cools too much before the desired compaction density is reached, strength and durability of the driveway will suffer.

For instance, paving at 2 degrees centigrade is feasible for short straight driveways with access for the compaction roller immediately as the asphalt is laid. Thicker mats of asphalt aid in prolonging effective compaction time. On the other hand, wide driveways with complex shapes and many seams must have warmer temperatures to extend compaction time for joints.

9. Steps in Driveway Construction

Excavation of existing soil, clay, organic material and rocks until undisturbed sub-soil is reached.  Excavation can be as little as 50 to 100 mm with good sub-soil conditions extending to 400 or 500 mm when bad sub-soil conditions must be remedied. 

Installation of a base of aggregate (crushed limestone) and subsequent compaction with a vibratory roller. In the case of greater than 150 mm of new aggregate being required, the installation of aggregate is repeated with multiple layers of 150 mm to ensure full compaction. The top 100 mm (to 150 mm) aggregate should be less than 16 mm size; courses below this level are typically larger size (75 mm) for greater support capability. Then, final grading of the aggregate to obtain desired pitch and remove any minor depressions. Compact again

Lay the mat of Hot Asphalt Mix.  Once the foundation of aggregate is properly prepared with proper pitch and a level plane, dump trucks deliver the hot asphalt to the job site, a pad of asphalt is installed by hand at the garage sill to set depth of asphalt mat, skid steers will load the paving machine now positioned on the pad, and the paving machine makes the first pull down the length of the drive.  This can be repeated for drives wider than the maximum width of the paving machine.

Compaction (rolling) of the mat to 90% to 95% of maximum density follows laying of an asphalt mat.  Compaction with vibratory drum rollers ensures the asphalt is achieves density and ideal strength characteristics.  Note: even greater density can be achieved but this degrades longevity of the asphalt driveway by eliminating some the flex inherent in asphalt layers and creating micro-fissures allowing water penetration.  Over-compaction is evidenced by white (bare) gravel edges showing on the surface of the new black asphalt surface.

10. How long before I can drive on it?

We recommend that a residential driveway be allowed 3 days to set up after asphalt paving.  Yes, the driveway top surface will cool to ambient temperatures within several hours, but the core remains hotter.  Asphalt cement in the Hot Mix slowly cures and strengthens for 90+ days after paving.  The extra inconvenience of keeping cars off the new driveway for three days eliminates any chance of premature damage.

Because curing of asphalt is a slow process, we recommend that homeowners vary their driving and parking pattern on the asphalt surface as much as possible for the first 90 days.   Alternately park near the house, then near the road, left of centre / right of centre.  And avoid traffic within 25 cm (10 inches) of the chamfered edges; stress cracks may result in the new asphalt mat.

11. How long will my new drive last?

A properly constructed asphalt driveway should last 15 years or more. We see many driveways that have lasted 20+ years. However, to last this long without heaving and collapsing, the foundation of the driveway must be built on soil that drains, native marl or gravel, and not have rocks, clay and organic materials present. See more on this topic on the Frequently Asked Questions drop down menu "Aggregate Base: The Foundation".

12. Territory served?

Free Estimates for: CALL 613.394.6196 BELLEVILLE - TRENTON - BRIGHTON - FRANKFORD - STIRLING NAPANEE - DESERONTO PICTON - BLOOMFIELD - WELLINGTON, PRINCE EDWARD COUNTY MADOC - MARMORA - CAMPBELLFORD - HASTINGS COBOURG - GRAFTON - ROSENEATH

13. Why chamfered edges on drive?

The 45 degree chamfer crafted on the sides of the pavement not only gives the drive a 'tailored' edge, but serves as a water barrier. When the aggregate foundation is being packed, a shallow channel is purposely dug along each edge of the aggregate surface. When paving, the Hot Mix Asphalt is carefully lapped down and into this channel, and later hand-tamped. The resulting chamfered edge that extends several inches into the surrounding soil prevents run-off water from undercutting and eroding the aggregate base from beneath the asphalt surface, thereby precluding collapse.

14. Why choose Trenton Paving?

We thank you for considering Trenton Paving. Trenton Paving has been serving residential and commercial customers in the Eastern Lake Ontario region from Cobourg and Port Hope east to Napanee and north to Madoc - Campbellford for 40+ years. We are not the largest paving company but we strive to be the premier paving company for residential driveways, small commercial projects and recreation courts in the Eastern Ontario region.