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Bosch Bostik Pro PU91 Polyurethane Construction Sealant 300ml Black

4.5 (42 reviews)
SKU: 240609120614004 EAN: 5010591013711
• Extremely elastic\t • High modulus\t • Bubble and primer free • Professional grade • Interior and exterior use BOSTIK PRO PU91 CONSTRUCTION POLYURETHANE SEALANT is a professional grade polyurethane sealant developed for sealing construction joints subject to high movement. This black PU sealant has a high modulus formulation and is extremely elastic with up to 25% movement capability. Suitable for interior and exterior applications, Bostik PU91 is bubble and primer free, can weather environmental stress, and is ideal for sealing joints that will experience a lot of movement and traffic, such as gallery floors in high rises, or warehouse floors. • Developed for construction joints subject to high movement • +/- 25% flexibility - allows for movement
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Customer Reviews 42

4.5
42 reviews
5 star
32
4 star
4
3 star
2
2 star
1
1 star
3
Not impressed
3.0
February 3, 2026
Dave Smart Verified Purchase

It's a dark pink, not brown. Not very east to work with.

Good stuff, needs a strong caulking gun.
5.0
October 28, 2025
5d173c2a-65be-5ce1-84c4-6b064f28d88a Verified Purchase

Used to fill and seal for an automotive application. It seems to be good stuff, remaining compliant and strongly adhered at the edges. It is quite viscous though, you will want a good caulking gun, it was quite a workout when using a basic one.

Shed sealing
5.0
October 27, 2025
frfr Verified Purchase

Used to seal a timber shed along with louvre vent fly screen. It sticks well in the timber and it claims to be elastic, so time will tell how long it lasts.

Works well for bonding windscreens in place.
5.0
June 29, 2025
03141652-10c8-5a49-9e54-5cd34030a0b6 Verified Purchase

I used this to bond a replacement windscreen in place. It worked perfectly 1st time with minimal prep and no previous experience. It's formed a nice strong and water tight bond.

Reliable moisture cure sealant.
5.0
January 30, 2025
Supersskiparks Verified Purchase

Sticks the soles of my boots back on. Good moisture cure flexible structural adhesive/sealant. Not let me down so far, but can be difficult to remove.

Better than silicone? I think so.
5.0
October 14, 2024
Graeme Yorkshire Dales Verified Purchase

Had the tube (unopened) for almost a year before using, and it was still in good condition.
I filled larger gaps around window frame with appropriate filler and after masking the UPVC frames and stone openings this product was very easy to apply, and incredibly easy to smooth over with a soapy wet finger to give a good appearance. The compound set within a day and was very hard, but still slightly flexible, after another couple of days. A great product that I will definitely use again for further renovations.

Quality sealant
5.0
September 15, 2024
p38 Verified Purchase

Good quality sealant, used for filling around cable holes in outside walls

Helpful assistant.
5.0
August 11, 2024
Old Stu Verified Purchase

Very helpful assistant behind the counter. Great stock level.

Ok
3.0
February 21, 2024
Cun Verified Purchase

Tried to repaIr a seal. Didnt work but may have been outside the scope of this product

Proper sealant that leaves a professional look.
5.0
November 7, 2023
Tommy1982Y Verified Purchase

Thicker than other sealants I’ve used which definitely made it easy to work with and clean up afterwards. Would definitely recommend!

Spot on
5.0
September 26, 2023
Bobba Fettler Verified Purchase

spot on for my emergency repair and click and collect always good

Happy with this product
5.0
August 28, 2023
Liam mccormack Verified Purchase

Good product easy to work an easy ro clea area after applying

Good product, does what you expect.
5.0
August 28, 2023
Tom175 Verified Purchase

Good stuff, easy to use. I like the pierce tip rather than having to cut the end off. Grand stuff!

Works fine
4.0
August 18, 2023
Ponytailpaul Verified Purchase

Did the job I wanted it to do, hopefully I got it sesled so I can use agsin

Lack of product
1.0
August 14, 2023
Woody Peter Verified Purchase

You advertised in your catalogue a 150 mm hopper code 50528 but have none in your shops or wear house or could give me a date when you would get some. Poor service

Does the job
4.0
August 9, 2023
Comeonroth Verified Purchase

Its not a bad product but because its a Polyurethane sealant it is difficult to tool. I would suggest using masking tape to define the joint being filled.

Great product easy to apply
5.0
August 6, 2023
The webster Verified Purchase

This is a great product nice consistency easy to use and applyeasy to smooth

Wonder product
5.0
July 21, 2023
David Meredith Verified Purchase

Great product. Used to fix a washing machine seal. Ten washes so far, no leaks. Saved me £100!

Waterproof mastic
4.0
July 19, 2023
R A B Verified Purchase

Very sticky - Adheres well to skin so gloves required. Light grey colour

WRONG COLOUR
2.0
July 17, 2023
9okfspd5eb825653h93grzon1 Verified Purchase

I ordered 6 grey and received 4 grey and 2 white. Not happy

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