FAQ's

1. What is the main advantage of 790-11 over other waterproofing systems?

 

Its main advantage, apart from being extremely cost effective as a waterproofing system, are that it forms a 100% bond to the deck eliminating the possibility of water tracking between it and the deck.

It is monolithic once complete. No laps!

 

2. Is Bakor 790-11 a Reinforced System?

 

True Hot Melt Systems utilize a Polyester Reinforcement Fleece between 2 no. 3mm layers of 790-11 Hot Melt compound. Research has shown that the best way of eradicating the effects of pin-holing is to employ a 2-layer reinforced system.

 

3. Why specify 790-11?

 

Clarifying the advantages. 790-11 is a fully bonded system. A fully bonded system limits water migration even if damage occurs. 790-11 allows a building or structure to be made watertight in a hurry. It is not unusual for an experienced crew to install in excess of 1,000M2 per day?

 

4. What substrates can 790-11 be applied to?

 

There are many types of substrates that 790-11 can be installed onto including:

 

In-Situ Concrete

Lightweight Concrete in Structural Metal Trays

Pre-Cast Concrete Planks

Brickwork

Concrete Blocks

Exterior Grade Ply

OSB3

Calcium Silicate Boards

CLT Panels

Metal Plate

Bituminous Membranes

 

5. Should I look out for Surface Treatments on In-Situ Concrete Decks?

 

Surface Applied Curing Compounds are sometimes used by the In-Situ Concrete Deck installer to aid and protect the curing process. Some of these compounds have a detrimental effect on the bond of 790-11 to the deck. Bauder should always be informed if these compounds have been employed for comment on their suitability.

 

6. What testing method should be used for ensuring In-Situ Concrete Decks have cured enough or have a moisture content conducive for 790-11 to be installed?

 

The industry recognised test within the UK is the Peel Bond Test. At around 14-21 days after in-situ concrete has been poured we use the Peel Bond Test to ascertain whether the concrete has cured enough to provide a good bonding environment with our 790-11. The Peel Bond Test mirrors the specification. A layer of primer (Polymer or bituminous) is laid on a clean concrete area. Once dry a layer of 3-4mm of 790-11 is installed over the top with a patch of protection sheet laid into it when warm.

The size of the test area should allow for 2 tests. One on day of installation and one 24 hours later.

Cut 2 sides of a triangle through the protection sheet down to the deck. Pull the sample from the point. If the sample sticks to the protection sheet and not the deck this is an adhesive failure (FAIL), if the sample sticks to both the deck and underside of the protection sheet but pulls apart by the product parting this is called a cohesive failure (PASS).

If you gain a pass wait 24 hrs to do a second test. If the pass is replicated you are good to go.

 

Other methods that can be used are:

 

Moisture Meters – These can measure the moisture content remaining within the deck hydration process. 4 to 5% at 75% RH would be a pass target.

Plastic Sheet Method – This can be used as a quick guide to see whether a full-blown Peel Bond Test is worth carrying out. Basically, a plastic square is taped to a dry deck, sealing it. Wait 16-24 hours and peel back. Any moisture on the deck or underside of the plastic would indicate that too much moisture is still present within the in-site concrete for successful adhesion of the 790-11.

 

7. Can 790-11 be used on zero falls roofs?It can, as detailed in our current BBA Certificate. It must be remembered that zero falls is a completed roof deck with a fall of 0 to 1:80. There should be no back-falls.

 

8. What is the life expectancy of our 790-11 Hot Melt System?

 

Our BBA Certificate gives our 790-11 Waterproofing System will provide an effective barrier to the transmission of liquid water and water vapour for the design life of the roof in which it is incorporated.

 

9. What things should be borne in mind when specifying EPS or XPS Inverted Insulation?

 

The following items should be considered when specifying:

 

a) Wind Uplift – In areas of high risk, tall buildings etc we would recommend a wind uplift calculation is performed to confirm ballasting requirements.

b) Flotation – all EPS or XPS inverted insulation needs to be ballasted to prevent floatation.

c) UV degradation - EPS or XPS inverted insulation should be covered by its WFRL and subsequent surfacing as soon as possible after installation.

d) Fire Risk - EPS or XPS inverted insulation should be covered by its surfacing as soon as possible to prevent any risk of fire at construction stage.

e) U Values – Care must be taken with u value comparisons between different manufacturers inverted insulation. Design lambda values can vary making thickness comparisons tricky. Preference would be that each project has a calculation carried out to confirm thickness against specifier target u value. Always check to see whether insulation is incorporated to the deck underside as this could impact on the thickness requirement for the inverted insulation above deck. If requesting u value calculations, advise where in the country the project is located (post code required), as rainfall levels can change based on location.

 

10. Which outlets are recommended for use with 790-11?

 

As a minimum, an outlet with a clamping ring should be used. Our Bauder Hot Melt Compact Vertical Outlets are ideal or any cast aluminum outlet with clamping ring can be used. We do not guarantee the seal to Non Bauder outlets.