air tightness issue

[ProDave]

There do seem to be a lot of cables through the membrane,  Why?

 

Obviously mains in, telephone / broadband in, and water in need to penetrate the membrane. Those come up in the utility room in our house, each individually sealed where they come up.

 

A few outside lights. That is a single cable to each, with just a small hole just big enough for the cable and the single cable entering taped to the membrane.

 

All tv aerial etc and some notwork cables all come up through a hocky stick that enters into the AV cupboard under the stairs.  With all cables in place, the ends of the hockey stick were foamed to seal the remaining space.

[Iceverge]

3 minutes ago, Redbeard said:

get some OSB/ply behind if you can (as it's a darn sight easier to stick to something which doesn't move away from you!)

 

Agreed completely. 

 

Membrane is great for long uninterrupted spans. Cheap, fast very few joints needed but it's not very robust and impossible to tape in tight corners. 

 

Use PLY/OSB and airtight paint/sealant here instead. 

[Jenki]

1 hour ago, JackofAll said:

To be honest I never thought through the wiring routes so buck stops with me at the end of the day. This morning I had a good look round and there were many accidental holes that need to be addressed. Place is like a golf course, Disappointed is an understatement. Just another job added to the ever increasing list.

I used a lot of sad emojis on your photo's due to the lack of a suitable  fe**king mad as f*ck emoji .

 

With self build you have to see the positives in all situations or you will want to jump off something high all too often.  The positives are  you've seen it, and thus can fix it. 👍 and hopefully prevent more happening...

In my opinion, your not fixing this with grommets unless you pull the cables. 

As @Iceverge points out sealant will be the best way forward.  Deep breaths, re group, crack on...

 

[JackofAll]

1 hour ago, Iceverge said:

 

Here's how I did the wires into the attic. The pic is taken looking down from above. A scrap trapezoidal piece of ply screwed to the trusses from below. The membrane cut back and tapes to the ply.  It doesn't need to be pretty but it needs to be neat and effective. 

 

ONE WIRE for ONE HOLE. 

 

No expensive grommets needed, just a squirt of airtight sealant from both sides. The sausage gun can be seen. Note there's plenty of space between the holes. 

Tasty, will order the sausage today, thanks lads. Will definitely be taking you up on the fan. It will be a massive help, much appreciated.

[JackofAll]

Can definitely say I've been stressed today, have a hiatal hernia and felt like it was coming up through my throat earlier. Now, I have to take responsibility as was  mentioned earlier, planning route of cables. We have ducts coming up through floor for outside services in the plant room, just never thought of the routing for sockets, switches etc. A valuable lesson learned, as was communicated to herself earlier, "will know for the next one", 😉

[Redbeard]

7 minutes ago, Jenki said:

In my opinion, your not fixing this with grommets unless you pull the cables. 

 

Yes, my suggestion of 'grommets-with-a-slit' was effectively to give a substrate to work off, similar (but not as strong as) @Iceverge's ply. Each 'cut grommet-hole' would still require Tescon tape or butyl tape to complete the job.

[JackofAll]

 

I used a lot of sad emojis on your photo's due to the lack of a suitable  fe**king mad as f*ck emoji . 😀

[JackofAll]

1 minute ago, Redbeard said:

 

Yes, my suggestion of 'grommets-with-a-slit' was effectively to give a substrate to work off, similar (but not as strong as) @Iceverge's ply. Each 'cut grommet-hole' would still require Tescon tape or butyl tape to complete the job.

Am not adverse to asking for the cables to be pulled and redone, though it was hard enough to get him to site in the first instance.

[Redbeard]

 

24 minutes ago, JackofAll said:

Am not adverse to asking for the cables to be pulled and redone, though it was hard enough to get him to site in the first instance.

If that's the case the question then is 'where do you run the cables now?' I don't know what sort of house you have, but is a service void feasible? If it is, and you get the spark to pull all the cables, you'll still have to seal all the holes in the membrane, but you can then run all the cables *inside* the a/t layer, except those few which have to breach it, and you now know how to do even that with fewest risks.

[Kelvin]

55 minutes ago, JackofAll said:

Am not adverse to asking for the cables to be pulled and redone, though it was hard enough to get him to site in the first instance.

I wouldn’t do that as it could cause you different problems. Figure out how to fix the problems you have. It’s all doable with a bit of thought, care, and the right products. 

[JackofAll]

2 hours ago, Redbeard said:

 

If that's the case the question then is 'where do you run the cables now?' I don't know what sort of house you have, but is a service void feasible? If it is, and you get the spark to pull all the cables, you'll still have to seal all the holes in the membrane, but you can then run all the cables *inside* the a/t layer, except those few which have to breach it, and you now know how to do even that with fewest risks.

We do have a service cavity, its was just the lack of a plan on routing back to board. Have ordered sausages.