Mastic, silicone, sealants and foams.

[Nickfromwales]

We’ve been using Passive Purple again, on the current (now pretty much an EnerPHit level refurbishment of a masonry dwelling) and it’s good stuff.

 

When you’ve lots of nooks & crannies to seal / tape, and a mixture of substrates, then this just seems to be a great product.

 

This plus a boatload of FM330 foam, and some meticulous membrane and taping, should get us in good stead for the arrival (soon) of AeroBarrier to put the cherry on the cake. 

 

Anyone wanting to go airtight and are in need of a paintable solution, or one you can spray through a HVLP gun also, then chat to Adam and the team at Intelligent Membranes, and they’ll give you support and advice a-plenty. Great people who have bent over to help out with technical (and practical!) advice; both on and off site. 👍👌

 

They’ve expanded services and products a lot so worth checking out if they have anything to make life simpler / the job (and end results) better   

[Alan Ambrose]

A couple of questions:

 

+ anyone used ROTHOBLAAS air tight tapes instead of Pro Clima? e.g. https://insulationmerchant.com/products/rothoblaas-seal-band-60-airtightness-tape . I know their screws get proper SE reverence, so maybe their tape is pretty good also?

 

and...

 

+ there's a bit of a fuss re CT1 being maybe less than magic: https://youtu.be/bwvE9FqjfQA - anyone have any views?

 

[Onoff]

I've used Illbrück expanding tape instead of Compriband. Seems good. 

[Sparrowhawk]

I need to caulk our staircase: the new baserail to the stringer(?), the stringer to the plasterboard wall under it.

 

Can anyone recommend a caulk that flows like a dream, handles the movement of a 100yr old house, and overpaints without crazing? I've used caulks that do 1-2 of those, but not all 3.

[Oz07]

Some caulks say its the paint that cracks with the movement not the caulk. Don't know how true that is. Ive been using the crown own brand with a green label not sure if good for you though. 

[jack]

On 08/11/2025 at 16:32, Sparrowhawk said:

Bonus shout-out to Silicone grease which when popped in the cap has kept some nozzles from setting.

 

Missed this on my previous reading of this thread. Sounds like a great idea.

[Tetrarch]

For silicone-ing the join between ceiling and ceramictiles I've just bought a tube of Dow 785 that I have used for ages. My previous experience is that it stays white and is easy to tool

 

Given the advice above should I consider swapping it out for CT1?

 

Regards

 

Tet

 

PS Cramer/Fuji tool and following Charlie DIYte's youtube video for the best results

[Onoff]

5 minutes ago, Tetrarch said:

For silicone-ing the join between ceiling and ceramictiles I've just bought a tube of Dow 785 that I have used for ages. My previous experience is that it stays white and is easy to tool

 

Given the advice above should I consider swapping it out for CT1?

 

Regards

 

Tet

 

PS Cramer/Fuji tool and following Charlie DIYte's youtube video for the best results

 

I'd use Forever White or BT1. Both have fungicide in them. 

[Nickfromwales]

23 minutes ago, Tetrarch said:

For silicone-ing the join between ceiling and ceramictiles I've just bought a tube of Dow 785 that I have used for ages. My previous experience is that it stays white and is easy to tool

 

Given the advice above should I consider swapping it out for CT1?

 

Regards

 

Tet

 

PS Cramer/Fuji tool and following Charlie DIYte's youtube video for the best results

The white CT1 has a tendency to discolour, from previous experience, but may now be improved / resolved.

 

Also, CT1 is an absolute pig to even attempt to tool or shape / finish so I’d avoid for that application.