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i've tried removing the trap, but whilst it spins around it doesn't budge easily and I don't want to force it.

We moved into our newly plumbed house in May. Some 4 -6 months in, I noticed that the shower wasn’t draining very quickly. It wasn’t flooding the wet room, it just didn’t seem to clear efficiently, which was odd, because the shower is on an external wall and on the other side of that wall, 3.5m down is our new sewer pipe taking water away to the sewer. It has progressively got worse and today a 12 min shower partly flooded the bathroom. Since I noticed the problem last year, I have been lifting up the tiled slot drain cover to inspect for anything that may be blocking it, and never found much, other than the occasional bit of SWMBO’s hair. However, today I noticed a black film of gunk all along the underside of the cover. Scraped it off into the bin. I suspect the same gunk has lined the pipes and narrowed them? Is that possible? The shower still drains fully, it’s just got progressively slower and has surprised me given we could have taken more than 500 showers there between us, and the plumbing was brand new! My pipes are plastic, so I’m nervous about using strong chemicals to clean it. But is this method, courtesy of Google, safe to do with plastic pipes? First, pour roughly a cup of baking soda down the drain (no exact measurement needed). After a few minutes, pour an equal amount of vinegar down. Leave the mixture sitting for at least an hour. Follow up with another round of boiling water, and see if the shower is draining faster.

We actually en I can't now find the technical data sheet, but we laid R10 tiles on our outdoor patio and they are absolutely fine. I wouldn't want to walk on it on ice, but in rain it is fine. For the shower wet room, we used the same tile as outside, but in a slightly different size. It would have been R9 or R10, probably R10 but can't be sure. Conclusion: R10 (at least in Marrazzi tiles) is absolutely fine for wet rooms.

Thanks @Temp, this just makes me think it should have been commissioned in room temperature-dependent mode.

no. don’t these two statements contradict each other?

Yes, it’s a system boiler. There are thermostats for each zone, on timers. The boiler should only come on when a thermostat calls for heat. But this wasn’t the case on Saturday 30h or so after the last call for heat.

@larry has the same boiler, so curious in what mode his was commissioned.

Indeed. Just curious as to other’s thoughts on the utility of a continuous operation mode. Maybe @Nickfromwales will chime in with some views.

You don’t want softened water for your garden. It will affect some plants, because of the extra salt. It’s debatable whether softened water is okay for human consumption. Some plumbers insist it isn’t, and I’m surprised your plumber didn’t separate a fresh un softened supply for drinking. But some members here think that unless you are drinking gallons and gallons a day, the salt levels are too small. I wouldn’t want to drink softened water though.

We are away on holiday and have a friend checking up on the house. He called me up to tell me the boiler fan was running and some adjacent pipes were hot. At the time this observation was made, the thermostats in the rooms and HW for the cylinder had all been off for 30h at least. Fishing through the various menus on the Viessman (a Vitodens 200W system boiler), and consulting the manual it appears that there are three modes which it can be setup on initial commissioning: - weather compensated mode - continuous operation - room temperature dependent mode Im just trying to work out if this was a mistake on commissioning or if there might be a reason for choosing continuous operation? We have our system boiler installed with a low loss header. All our heating is UFH (four manifolds) except in two bathrooms, where we also have a towel rad in each one. My friend couldn’t seem to change the mode to “room temperature dependent mode”, so he has just turned the whole boiler off at the mains. I will investigate when I’m back home, but it was commissioned 9 months ago and because we have the hot water tank heated by the boiler three times a day plus a recirculating secondary loop that comes on wherever you’re in the room where the boiler is, I had assumed the hot pipes were from that - never noticed the boiler make any fan noise when it was meant to be off, so I wonder if this is a mistake at the time it was commissioned, or an issue that’s developed since. I attach a screenshot from the manual; it doesn’t give much info:

I agree with your assumption. But does this account for the following: whilst it is obviously perfectly comfortable to shower in a 27C bathroom, it would not be comfortable to sit on the toilet in one that hot for very long. The reality of most houses with MVHR is that it is the hot water from the shower/bath that raises the temperature of the room whilst it is being used for showering/bathing and that heat is cleared by the boost on the MVHR being active for 20 or so minutes after showering/bathing or longer if boost is not used.

Samples arriving soon. I will post pictures when they do.

Good to know! The two contenders are: The 3-8mm one which looks fairly angular in these pictures, but the intended "applications" on the website lists various things EXCEPT it doesn't list paths, which is somewhat of a red flag! The 14mm to 20mm one does say "Suitable for low traffic gravel driveways & footpaths", so maybe this is best. Here are the pics.

I read somewhere that 10mm stone was the recommended size for a footpath made of gravel. However, SWMBO has fallen in love with one gravel which is described as 3-8mm and another which is described as 14mm to 20mm. FFS! Are either of these sizes viable alternatives? I imagine the 3-8mm should be quite comfortable to walk on, but likely to get stuck in the bottom of people's trainers, whereas the 14mm to 20mm will be slightly uncomfortable if you walk on a 20mm pebble that is otherwise surrounded by 14mm stone. Shall i just stick to 10mm?

I don't think what I said is contradicted by what you've quoted. I said that MVHR won't equalise the temperature across a building. It will increase the temperature of the colder rooms marginally and decrease the temperature of the warmer warms marginally. I estimated the margin to be about 0.5C. The material you've quoted says: "The Passivhaus standard suggests assuming an internal temperature of 21 °C and to a certain degree the use of MVHR evens out the temperatures of different rooms providing uniform temperatures throughout the building." (my bold emphasis) Ultimately, it's horses for courses. My house is not close to being passiv standard. We have insulated a 1930s semi as well as we could, upgraded the glazing to 2G and installed 3G rooflights. We have a very efficient MVHR system and there is a 3 degree variance between the coldest room in the house and the warmest (at the moment). I imagine a better insulated house with 3G windows might have less variance.

I'm not sure about this logic. MVHR will not equalise temperatures within a house, because flow rates are too low. It might make warmer parts of the house, a little cooler, I estimate 0.5C or so cooler, and colder parts of the house a little warmer, I estimate 0.5C warmer, but it's unlikely to move the needle much beyond that unless you ran the ventilation rates on max all day, and nobody would do that because it would be noisy. Ultimately the purpose of MVHR is to constantly ventilate a house with fresh filtered air, without losing the heat that is already in the house to the outside. So air of varying temperatures is extracted (say 22C plus from bathrooms and kitchens) and that heat is transferred onto the incoming air which gets distributed to the rest of the house, but not in sufficient volumes to really increase the temp by much more than 0.5C or so.

So just to update: the windows company came back and tightened “the mushrooms” which are apparently what holds the window latches when the handle is closed. This has fixed the issue with the draught by the sofa. It turned out that was the only window affected. The other one was actually ventilation coming from the MVHR!

I’m really surprised by the title to this thread. I think MVHR is amazing. Probably one of the best “green” aspects of my renovation. I went out for dinner with some friends the other day who were complaining about how much it costs to heat their house, and how they have lots of draughts but still have condensation problems. I couldn’t help feeling smug that my bills haven’t been too bad this winter and the house never feels cold, smelly, damp or draughty (especially now we got the window fixed).

It’s not too late. Would you mind posting a link @oldkettle? I’ve youtube searched “Robin Clevett shelves” but not found anything that looks right. I’m familiar with him; would be good to see the video. Unless this is the company: https://www.cutwrights.com/new/ ?

But if you look at that table, in the row above the row that talks about “solar protection” there is a “solar gain” row. And that says that there is less solar gain on the 60 model (which is 2G) than on the 66 model (which is 3G).

The internal ones definitely are. The external ones are in theory, but in practice it is quite involved and I’m worried about bodging it. I’m also not very agile and I would probably struggle on the ladder: one of the Veluxes in question is above a stairwell, so very tricky to access, whereas the other is above a flat floor, but still quite high up, the bottom of the Velux being about 2.8m from the floor.

This isn't always true (at least not the first sentence). If you use a good manufacturer, then it probably is true, but distinguishing between "good" and "bad" in this area is a minefield. I had assumed Velux was a "good" manufacturer, but the devil is in the detail and it depends on the spec. For example, take Velux's Integra GGL range. Some of these rooflights come as 3G and others as 2G. If you look at the spec of the 66 model (which is 3G) and compare it to the 60 model (which is 2G) the 3G has a solar gain value of 0.52 whereas the 2G has a solar gain value of 0.3. So in this instance the 3G is letting in 73% more heat than the 2G model (52% versus 30%). I mistakenly specified the 3G thinking it would be better, but it's not. Compare the two tables on page 3 of the attached, which shows the 3G model uses slightly thinner glass and different gas. Velux download.pdf

I'm looking for a company to come and fit some external shading to some of my rooflights. Most of these are velux, so should be standard/mass-market enough for there to be some price competition. Yet I'm finding the prices are a bit high. I have been quoted a price to supply an external velux heat shutter £522 plus VAT and installation of £600 plus VAT. Seems a lot for what cannot be more than a day's work. It can be installed from the inside of the room, so no scaffolding needed and isn't really "dangerous" work. I can get the blind for £450 inc VAT if I purchase it on amazon, but then I don't get the benefit of having the same company supply and install (which I value, as it minimises the risk of different companies blaming each other). The one thing going for this company though, it seems, is that they do have very good trust pilot reviews. Of the 60 or so reviews, there are only two bad ones, with all others being 5 stars. One of the bad ones was about a complaint that arose 5 years after installation, which the company wanted to charge for because it fell outside the 3 year warranty period. So that seemed like an unreasonable complaint to me. I'm due to get another quote but so far this is the second cheapest, the cheapest not having the benefit of many online reviews. So the question is, are trustpilot reviews trustworthy?

Here is a photo of my gutter off my first floor roof, that is directly above a large skylight in my ground floor roof: when it rains, there is a fairly constant drip from the gutter onto the rooflight below, making a fairly noticeable sound in the living room under the skylight. One possibility is that it’s leaking, but I don’t think that’s the case. It appears that water hitting the sides of the gutter (which is of the rectangular, not curved, type) or the top edge, drips down the external side of the gutter and then onto the rooflight beneath. Is there anything I can do about this? Would adding a diagonal profile to the top of the gutter, for example, help to funnel water that would otherwise hit the side into the gutter?

Can somebody please explain what perceived benefit there is of using MVHR to keep a house cool? I have MVHR but I don't find it does anything to cool the house down in summer (even with summer bypass activated). The flow rates just aren't big enough for it to cool effectively.