ashtree
Bioengineer
- Nov 28, 2015
- 703
I am hoping you can help me with an opinion the suitability of the roofing system installation.
I do process engineering and manage water quality for a water utility and recently we have had built a new glass fused steel treated water reservoir at one of the water plants i work at. Everything had gone well and i got onto the roof of the reservoir to collect a sample(the first time up there) and i noticed that every sheet of the aluminium roof was lapped wrong both length ways and cross ways.
When this was referred to the contractor/supplier they said they always did this and stated that because they put sealing between the sheets it was not an issue. They also stated that only half the roof is lapped incorrectly because the roof falls away both sides from the high point.The roof is screwed in the valleys not the peaks. The install seems to go against all the well known roofing practices, but they have trotted out statements from the tank supplier and from the building inspector saying its okay. The construction drawings also seem to at least partially confirm that screwing the sheets on the valleys was intended.
My argument is that in order to prevent run off from the roof going into the treated water , you become 100% reliant on the sealant around the screws and between sheets. This is a contamination risk. On some sheets the sealant is obvious but many are not so we have no certainty whether sealant was even installed. A photo of one sheet is attached.
The contractor and supplier have dug their heels in as expected and have given me all the reasons under the sun why this is okay, but i am not convinced personally. Just because this is the way they normally do it does not necessarily make it good practice. But i would be interested to hear your opinions on the matter.
Regards
Ashtree
"Any water can be made potable if you filter it through enough money"
I do process engineering and manage water quality for a water utility and recently we have had built a new glass fused steel treated water reservoir at one of the water plants i work at. Everything had gone well and i got onto the roof of the reservoir to collect a sample(the first time up there) and i noticed that every sheet of the aluminium roof was lapped wrong both length ways and cross ways.
When this was referred to the contractor/supplier they said they always did this and stated that because they put sealing between the sheets it was not an issue. They also stated that only half the roof is lapped incorrectly because the roof falls away both sides from the high point.The roof is screwed in the valleys not the peaks. The install seems to go against all the well known roofing practices, but they have trotted out statements from the tank supplier and from the building inspector saying its okay. The construction drawings also seem to at least partially confirm that screwing the sheets on the valleys was intended.
My argument is that in order to prevent run off from the roof going into the treated water , you become 100% reliant on the sealant around the screws and between sheets. This is a contamination risk. On some sheets the sealant is obvious but many are not so we have no certainty whether sealant was even installed. A photo of one sheet is attached.
The contractor and supplier have dug their heels in as expected and have given me all the reasons under the sun why this is okay, but i am not convinced personally. Just because this is the way they normally do it does not necessarily make it good practice. But i would be interested to hear your opinions on the matter.
Regards
Ashtree
"Any water can be made potable if you filter it through enough money"