Dream Downtown Hotel

355 West 16th Street, Manhattan, New York, NY

Waterproof Exterior Substrate with Difficult Penetrations

Property: Dream Downtown Hotel
Location: 355 West 16th Street, Manhattan, New York, NY


Waterproofing the exterior substrate of this large Manhattan hotel which had difficult penetrations, particularly around the large round recessed windows at varying degrees of depth, the result of, an existing sloping wall. Finding a solution to allow PC 88 and Foam Glass (an aesthetic look to show behind openings in the metal panel system) to adhere to the underlying waterproofing system. Repairs to the waterproofing membrane caused by prolonged sun exposure due to job shut down for 6 months.

1. Primary waterproofing system behind the hard stucco system received Henry Air Bloc. If installed on new sheathing at the recommended thickness, the material had a tendency to form blisters.

2. Installation of a new roofing system over newer concrete that had been left exposed to the elements for a lengthy period of time where moisture would be an issue for installation. Dealing with the multiple and varying type of penetrations in tight conditions.

3. Placing pavers and stone ballast on the various roofs that had tight access and limited room to move.


Working with waterproofing supplier Henry and buildings design consultant team an installation method was devised to relieve the tension caused by heating and cooling cycles at curved areas around the windows by pie cutting the blueskin into segments up to the point where the folding over to the return was to occur. Once that had been done, the pie cut pieces where sealed with Henry HE-925 sealant. Working with Henry and Owens Corning compatibility issues between blueskin and PC88 were overcome by adding a layer of cured Airbloc-21 prior to placing the PC88 and Foam Glass. Repairs to the waterproofing due to overexposure was based on careful inspection of all areas and removing the film that separated from the membrane and then reapplying new blueskin to the damaged areas and sealing with HE 925 sealant.

Solution was to apply a layer to the dense glass and then scrape off leaving only a thing film. Once that had dried, come back and apply the recommended thickness which greatly reduced blistering.

The concrete roof deck was given several weeks of rain free weather to dry out. Then a temporary roof with primer was applied per Henry specification. Once the roof deck was water tight it was allowed to sit and give a chance for it to dry out further from underneath as the building was being heated. Once the 790-11 roofing system was ready to be installed after most of the penetrations had been made, the temporary roof was checked for any blistering and damaged areas were repaired. This was then used as a base layer to apply the 790-11 system over the various roofs.

Patience and good cutting skills were essential in placing the pavers as had been approved in the shop drawings and as field conditions dictated. Additionally, the pool deck pavers required extra attention to detail given the large amount of cutting that was needed due to planter boxes and other obstacles. Additionally the ‘4 FEET DEEP NO DIVING’ wording that was etched into the pavers around the pool itself proved to be difficult at the two ends of the pool.

Services Performed

Waterproofing the exterior substrate behind the metal panels and the stucco system with Henry Blueskin and Air Block 21 (95,000 SF). Installation of Sto Hard Coat stucco system over cement board. Install Roofing system using Henry 790-11 hot applied asphalt (24,000 SF) to a series of 3 building with some new additions, and compensating for existing conditions.

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