A few weeks ago, we were asked if we could do a bird proofing survey on a railway bridge in London. The unusual thing was that instead of traditional bird netting, we would need to provide and install 12 SWG weld mesh sheets as a bird proofing method.
The site itself has some historic significance. It was built in 1836 by Colonel Landmann and consists of a brick arch, supported by 12 cast iron Doric columns. This bridge is one of two surviving bridges from London’s first railway line, so is a National Railway Heritage Site. Over time, metal girders were added to each side of the original bridge to provide support for modern trains. This is the area where pigeons had made their home.
In the past, several attempts have been made to bird proof this bridge, all of which have not been adequate or have not lasted. The local council have just renovated this bridge and so it is important that the pigeons are kept away from the underside of the bridge, both from an aesthetic viewpoint but also from a public health perspective.
Over the years, the pigeon problem on this site has become very bad. The quantity of bird faeces produced on the footpaths and the evidence of nest building would put the population in the hundreds, all living under this one bridge.
The specification for this work was pretty rigid, we had to use 12 SWG weld mesh sheets, nothing can be drilled, so all fixings must be clamps, the structure must provide total exclusion so no pigeons can ever gain access to the inner sanctum of the bridge structure, and it had to be removable and replaceable so maintenance can be preformed on the bridge as required.
Our final design incorporated all the above, but we included a few extra safety features and a different design method that had not been seen before, giving us the edge over our competitors, and hence then won the contract.
So why would you use weld mesh rather than traditional bird netting?
Firstly, if done correctly, this solution will provide maintenance free service and last forever. All bird netting will require service at some point. Secondly, bird netting is prone to vandalism especially in this type of environment. Once it is breached, the netting becomes a death trap for birds; they often get in but cannot get out. Thirdly, in this rugged environment, weld mesh does add to the overall effect of the bridge, especially as the bright-galvanised steel weld mesh contrasts with the deep blue of the new paintwork. Weld mesh is an ideal medium for proofing utility type constructions due to it’s long life and low maintenance – it might be more expensive initially, but will give a very good return on investment as opposed to normal bird netting.
This job called for meticulous planning, especially as we were working under extreme environmental conditions and at great height. It was also very physically demanding, especially with early mornings and late nights to meet the deadlines and working in cramped unpleasant conditions. We used scissor lifts to reach right up into the bridge roof, and again the constant motion of these MEWP’s is very tiring, but it’s the only way to get the 2.4 x 1.2mt sheets of weld mesh into the roof.
As outlined, the sheets had to be clamped in place using bridge and girder clamps, with each clamp needing a neoprene rubber strip and all bolt having locktite anti vibration fluid applied so they cannot come undone due to vibration of the trains passing overhead. I never know how creative we would need to be in cutting and shaping the weld mesh to go around birders, bolts and other obstructions to make it all fit!
One of the main problems faced in any bird proofing job is making sure no pigeons are trapped inside the wire mesh netting once it was finished. Rest assured they would try everything they can to get back in; after all they are homing pigeons and will always return to where they were born. To ensure this did not happen, we used temporary bird nets to seal off sections as we finished them and used klaxon horns, flags and whistles to keep them out.
We had to plan our work around footpath closures and other contractors on site, but finally we were in a position to seal off the netting. This meant a final inspection to ensure all pigeons were out of roof, then fitting the last sections of the weld mesh. Once this was completed, we moved to the outside of the bridge to bird proof the outer ledges where the pigeons had been forced to move. I have to say it was great to be working in the sun again after being in almost complete darkness under the bridge. Most bird proofing projects use multiple methods of proofing and this was no exception as spikes were used as well as weld mesh netting.
We had some brilliant feedback from the client and also the site manager at the end of the job. Basically the design we used met and exceeded what was required, and the site manager’s report gave us an outstanding rating in terms of workmanship and site safety, which is what we always strive for anyway.
This was a challenging project but we competed it on time and to budget and the team really worked well to make this a job to be proud of. We are very pleased that we have been involved in preserving this little part of London’s historic railway network and that we had rid them of the pigeon problem they once had.
So if you have a structure that has a pigeon problem, protecting it with a permanent maintenance free bird-proofing solution using weld mesh could be the best answer. Contact Rapid Environmental Services now for a free consultation and advice on a bird prevention solution for you.