Oxbow16

Hi I'm finishing a lead flashing job and now need to seal the flashing that's turned into the chase. The lead has been fixed using hall clips. It's an old stone wall, with undressed stone. So nothing is straight or flat! Although some seem to favour mortar, I've decided to use lead sealant. Some of the sealants specify that a width to depth ratio of 2:1 must be used (I guess at the end of the say this is a silicone, and the same ratio is also specified for other silicones such as sanitary types, etc). Where this ratio cannot be achieved what might the implications be? Having read/watch videos about the topic, it has got me to thinking. Lead flashing is commonly used against brick walls. The typical mortar joint is 10mm wide. The recommended chase depth of the lead is 25mm. So in this scenario, there would be a width to depth ratio of 1:2.5 and therefore well off the recommended 2:1 ratio. In fact, here's a couple of manufacturer's videos which seem to show the full depth of the chase being filled with sealant. The brickwork looks standard, so I presume the chase is no more than 10mm wide. especially at 1:29. at 6:30 Similarly, I can't imagine every plumber using silicone adheres to the ratio. So I wondered whether you guys think about this ratio business? Cheers

Good weather and a BH weekend, so hoping to get something done with this this weekend... If nothing else, I was thinking to remove the existing knackered fillet, repair obvious cracks and defects in the ground-wall join with a concrete repair mastic, followed by a new fillet. I figured and hoped that if this worked in the past hopefully it will again. I've no idea what mix of cement to use, whether to use SBR, etc. - so any thoughts on that would be great. And with the additional info and measurements I added last week, any other thoughts most welcomed too. Many thanks

Hi Got a few more details to add... I've measured up and the ground level outside is 230mm lower than inside (including the two layers of tiles on the inside, without those it's more like 170-180mm difference). The DPC (if it is in fact the DPC) is 160mm above ground level. I'm not sure tbh, but I was thinking maybe a bit of both. It has been ridiculously wet recently and over winter generally. Locals say it's the wettest they can remember. But also, as you can see in the photos, the old fillet (is that the right term?) is in quite a bad way and was possibly done in the wrong material to begin with. There are cracks all of it, some of it is loose. Plus there are cracks perpendicular and leading up to the wall. So yes, my thoughts were the abundant rain and the deterioration of the "fillet" were the likely cause. But replies here seem to suggest otherwise... Any further thoughts? Cheers

If the DPC was where the render finishes it would be well above the internal floor level. Wouldn't that be incorrect? The damp is at its worse at floor level on the inside, and then forms the rough shape of a pyramid/triangle. Around a foot and a half high. It's centred around that crack that can be seen in pic 2; the one that's perpendicular to the wall. The you mean the wall, ground, or both? How high - up the the roughcast? And replace with something else or leave it exposed? And what about the render beneath the crack/DPC? Could I ask why? If the concrete directs water away from the wall, what would be the issue? Not disagreeing, just trying to understand. I'd be a little scared to mess around with things so close the foundations. Also, if there was something softer there and the water drained, I'd be concerned about where it is draining to and the possibliity of it being trapped somewhere it should be (as opposed to being able to drain freely away). On top of all that, it's only recently become an issue and we've been in the house over 5 years. When we moved in there was no sign of a problem there, and that was with kitchen cupboards against the wall. So it would seem it's a recent development. I'd guessed it was either the previous repair failing (that peachy coloured stuff that almost looks like plaster!) AND/OR the perpendicular crack in pic 2. Thanks again for the great help, much appreicated.

Yes, sorry. I'm at work and didn't think I had any photos to hand but turns out I have. None show the context of the slope. But just imagine that in the first photo, the concrete slab continues out of frame to the right, and then drops vertically 4-5 feet. Does that make sense? I'll draw a little diagram if not. Thanks again for the help. PS - I'm presuming the long "crack" parallel to/beneath the pipe and extending beyond it is the DPC? What do you think?

The part of the house in question is a 1970s extension. The house is on a slope, so a metre away from the wall there is a 4-5 foot drop. So I don't think digging out concrete to create a gap would be the best idea tbh. Outside is a little lower; I can check by how much when I get home. I should add that the problem is quite a recent one and coincides with damage to the previous repair on that gap, which makes me think the previous repair was doing it's job until failure? Cheers

Hi There are some areas around my house where there's a gap between the concrete slab/path and wall. In at least one place the water is getting in enough to make the wall wet inside the house. What's the best stuff to use to fill the gaps? Should I look to fill the gap with on product, and then put in an angle section of concrete to add a second layer of protection and to direct water away? If I should be using concrete or mortar for the repairs, what mix should I use? Or am I barking up the wrong tree completely? Any advice much appreciated. Cheers

Hi I recently did some pipe insulating in my loft. The only two I didn't do were the vent pipes. Not sure if that is the right term for them? They are the pipes that feed water back into the top of the tanks when there is excess, presumably from steam, expansion, etc. The one going to the cold water tank is 22mm. The one going to the F+E tank is 28mm. I didn't insulate them because... 1. The water has to rise from the airing cupboard into the loft, UP the pipes until the very end where the pipes bend down through the tank lids. As such, water can never be sat in the pipes can it? And if so, it cannot freeze if not sat in it. 2. If both are used for excess, steam, expansion etc, then won't any water travelling through always be hot? Or have I missed something? If anyone could confirm whether they need insulating or not that would be great. Many thanks

Thanks for the reply Here's a diagram as it would be from the side if the fireplace wall wasn't there.... I should add that from what I remember the space around the flexi flue liner is not all that much at all. It's a narrow space. Perhaps that's why vermiculite wasn't used? Not sure... Cheers

Yes, sorry, that's what I meant. I've amended the post to make it a bit clearer. The stove has only been in 2-3 years, so not looking to do anything too major. I know heat will be lost from the flexible flue liner and accept that. At this stage I'm just thinking about ways to stop the heat on the room side of the closure plate escaping into the chimney void. A lot of heat naturally comes up from the stove top (and the single wall flue) and does a good job of heating the closure plate which gets pretty hot to the touch. But I'm guessing with no insulation on the other side of the plate, the heat will transfer and be lost. Would insulation on the other side of the plate help prevent some of that? Cheers

Hi all I've got a wood burner installed in a builder's opening. Single wall flue into a flexible chimney liner. The thin steel closure plate is higher than the lintel in front - i.e. you can't see it when stood in front of the stove. I therefore often wonder how much heat gets "trapped" in that pocket of space behind the lintel, and subsequently escapes through the closure plate into the chimney void. So I've been thinking about insulating above the closure plate using mineral wool and wondered what people think to the idea? I've not come across much info of people doing that. Seems sensible to me but perhaps I'm overlooking something. I did mention it to the chimney sweep when he was last here and he was against the idea. Not sure how much I trusted his opinions though (on that and other things!). One of his concerns was the mineral wool combusting. I told him that in my limited knowledge it's not combustible but he wasn't having any of it! Any thoughts? Many thanks

Not many users of back rod here?

Hi all Got plenty of caulking and filling coming up... I'd not heard of backer rod until recently, and having read up a bit on it it seems there's many others who are unaware of it. The big name stores don't seem to sell it either, which made me wonder how commonly it's used... So, any fans of backer rod here for use in channels, chases, etc prior to caulking? On a more technical note, there's a fair bit of online chat RE open vs closed cell. Apparently, open cell is more pliable/flexible and better for squeezing into gaps but not good if it gets wet. Also, they say closed sell off gases when cut or torn which can cause problems and even cause the caulk to bubble. But that's mainly from US sites/forums. Here in the UK, there's not much talk of it and the shops that do sell it seem to just sell "standard" stuff (which is closed cell). Does anyone know anything about this open/closed cell business? Cheers

Thanks everyone for all the help today. I've gone for the 356 with the x3 speed settings. It has lower vibration that the 355, which is a big bonus for me. I managed to pick it up for £112 with a 35 piece accessory set AND a T-Stak case. Very impressed I was! And I've also hopefully got a further 20% off using Topcashback, which would make it a ridiculous £90 all in if that cashback pays out. It was from ebay. The Topcashback 20% is for today only. The eBay 20% voucher is until the 27th. If anyone wants details as to what I got etc let me know and I'll post them up. Cheers