Artificial Grass Shock Pad – Best Fake Grass Underlay

The artificial grass shock pad is a material placed directly underneath during the installation process of your synthetic turf. They are considered one of the most important components of your artificial grass system. There are different varieties of shock pad and all of them offer resilience for the player as well as reduce compaction within the playing surface. These are made from perforated polyethylene foam fused together with the purpose of protecting children and sports players from falls, and absorbing the impact to reduce the risks of injury. Aside from those two places, there are also those that install shock pads on roofs and other concrete areas. This is because it prevents water from collecting in such areas with its well-designed drainage system. 

Shock pad underlay for artificial grass has a spongy but firm feel that makes it ideal for outdoor play use.

Shock Pad Underlay For Artificial Grass – How It Works?

Fake Grass Underlay

Sports complex use

The artificial grass shock pad is commonly used in sports complexes where artificial turf is installed and high-impact sports are played. In fact, sports venues are amongst the greatest consumers of artificial grass, with franchises such as the NFL applying synthetic turf to its playing fields. Different sports have a variety of requirements for their playing fields and artificial grass shock pad manufacturers can develop their products to match such requirements. 

An example of this is the International Rugby Board performance specifications that ensure artificial grass fields can replicate the playing qualities of natural grass fields. These specifications have been developed through a test program for artificial grass that checks ball-surface interaction, player-surface interaction and the durability of the artificial turf. One thing they measure for player-surface interaction is the Head Injury Criterion which talks about the likelihood of head injury arising from an impact. This HIC can be used to assess safety as it relates to vehicles, sports equipment, and personal protective gear.

While no surface can guarantee completely eliminating injuries, artificial turf design and development have improved so much in the past few years. Over a five-year study, they have found that the installation of artificial grass foam underlay has resulted in 44% fewer concussion injuries combined, 43% fewer ACL injuries combined, 25% Less Time Lost to Long-Term Injuries, and 16% Less Time Lost to Short-Term Injuries.

Artificial Grass Foam Underlay

Artificial Grass Foam Underlay

Playground and Nurseries

Aside from sports complexes, fake grass underlay is also used in playgrounds and nurseries. As mentioned above, artificial grass foam underlay will protect children from falls and they also deliver a critical fall height. Critical fall height is the greatest height at which an injury can happen on a head-first fall. This is based on the highest designated play area or the height of the highest play equipment that a child can use during normal play. This measure was created because more than 200,000 children suffer injuries from falling from equipment in playgrounds. The thickness of your artificial grass foam underlay varies in relation to a critical fall height. 

Below is the available artificial grass foam underlay thickness varieties and their corresponding critical fall height:

Artificial Grass Shock Pad Thickness Critical Fall Height
25mm 1.2m
35mm 1.7m
45mm 2.0m

Shock pad underlay for artificial grass has been made into a legal requirement in schools, nurseries, and playgrounds where high play equipment is used. However, this is also increasingly being used in back gardens where high play equipment has been put up for children. 

Common Artificial Grass Shock Pad Failures

Considering how essential artificial grass foam underlay is to an artificial turf system, and how much safety issue hinges on it doing what it should do in the first place, it probably wouldn’t come as such a surprise that there have been playgrounds that needed to be shut down over the years because of concerns regarding fake grass underlay. Below, we explore a few important factors in the care, supply, and installation of shock pad underlay for artificial grass.

Storage and Care

Artificial grass shock pads are made from a specially selected variety of foams with varying thickness and as such, you can probably tell that it does not react to heat exposure that well. It is important to store shock pad layers well in such a way that they are not deformed or misshapen. Securing the materials when it is delivered to the installation area is also essential. Shock pad underlay for artificial grass will be harder to install when it is deformed and it has a chance that it will not perform its required safety criteria when damaged. 

Expansion and Contraction

Some installers believe that leaving 1/8 of an inch between shock pad panels for expansion will prevent the panels from curling when they expand, but this could be detrimental to the whole system. The padding will and does expand when the panels are hit with direct sunlight, but if the shock pads are placed early in the morning before it gets too hot, it wouldn’t be a problem. Depending on the area you’re working with, you may need several workmen to install the turf and immediately place in the infill for ballast in a timely manner to avoid issues. Once the infill has been placed and distributed through the turf, the system would be stable enough and thermal contraction or expansion will not affect its placement. 

Another issue with those gaps between each shock pad panel is that some contractors botch the job and leave too large of a gap. After about a year of play and foot traffic, those gaps could be seen through the surface and become too obvious. You may have seen some of these things where the issue isn’t really the seams of the turf itself, but the gaps on the artificial grass shock pad underneath it. 

It is also important to double-check that all shock pad panels have the same thickness in all of them. It can cause damage to the turf system if there are inconsistencies in these things. 

During Installation 

When it comes to the installation of fake grass underlay, there are a few guidelines that need to be followed. 

  • The fabric side of the panel should be facing up; the rougher and uneven side should be facing down. 
  • Precision is key when trimming around the play equipment base. There should not be any gaps around the equipment base.
  • Seaming tape is recommended to be used to secure the shock pad together. Doing this provides more stability in the playground system during heavy use and ensures that the shock pad doesn’t move during the rest of the installation process. 6-inch seaming tape is what we would recommend as those that are wider will lessen the flexibility of the padding. Make sure that all seams are secured with the seaming tape and all sections are glued together as you go, so the connections are tight and you won’t have to go back and re-adjust.
  • When installing in playgrounds, it is important not to lay the artificial grass seams in areas where there is heavier foot traffic, including slides, swing sets, climbing features, and play equipment exits. This is because the shock pad is flexible and seams will eventually separate if they are placed directly underneath such areas. 

Where we don’t recommend artificial grass shock pads

We have mentioned above where shock pads are essential (and in some cases, required by law) to be used. Don’t get us wrong, we really do believe that it is a necessity in a lot of cases. However, there are a few situations where we don’t recommend including a shock pad for your artificial turf system.

We would not generally recommend including a shock pad in your artificial grass system at home if you have pets – that is unless your furry friend plays a dog sport where you would need to cushion them from injuries. Since fake grass underlay is made from different types of foam, it will hold urine and bacteria in that layer instead of draining into the stone base as it should. When exposed to heat during the summer months, the smell of urine will be pretty pervasive.

For the average residential backyard, a shock pad underlay would also be considered an over-spec. We would instead recommend using a compacted stone-dust base in this case because those also drain well and has enough cushion to absorb the shock or a trip or surface fall. Unless you plan on installing high play equipment in the near future, a shock pad wouldn’t be of much use for you. 


A shock pad underlay for artificial grass is a helpful safety feature that you can add to your artificial turf installation. It will afford you that peace of mind and will ease your safety concerns, but it is not for everyone.

Basically, if there is not a chance of a child falling in your backyard from at least a 1.2-meter height, opt out of a shock pad. If you encounter similar risks, then it’s definitely something you should consider.