Rocket Ron

Thanks for the clarification. Looks like I’m gonna try the foam gun with a plastic hose first in that case. I take it even if I didn’t manage to get the skirting is 100% airtight. There is still a great benefit to insulate between the joists? At least a certain degree of heat loss will be mitigated.

Do we really want the floor airtight ? I was under the impression that some airflow would still be required to help with damp and Mold issues and allow the house to breath ? what I’m trying to do is minimise heat loss through the floor

This is a Period property. There is no way the skirting boards are coming off after having re-plastered all the rooms it has to be done from below and I won’t leave any gaps.

Thanks for the info if my choices are only 4 inches do I go for the 140 mm or 90 mm thickness?

Because it’s such a large floor space, I think I’m gonna have to go with rockwool loft insulation as the surface area of the floor space is close to 100 m²

Yes I’ve got access to the entire under floor of the house. There is only one section that is very very tight but that has plywood Floor on top so I might access through a hatch that an electrician has made prior to today otherwise I have full access yes there are partition walls down there but there are holes in them for crawling through.

Thanks all. This is an Edwardian house that is huge. I was surprised that it only has 4 inch deep joists. I’m talking about thermal insulation installed from the crawl space just to be clear. it’s it’s going to be a horrible job, but I think it will pay dividends well I hope it will. No, it’s a case of finding the right material to use as already mentioned I will check out frametherm

Hello everyone we have recently purchased a bit of a monster Property and taken on a bit more than I can chew however insulation is a priority. The ground floor is a wooden subfloor with about a 70 cm crawlspace. All the joists are 4 inches tall not 6 inches and I wanted to insulate it with Rockwall and netting from below without lifting any floorboards because the floorboards have all been sanded and varnished and I do not want to damage . Kingspan is just not an option. The joists do not run true and the distances between the joists or vary by an inch two besides which getting the material under the floor is virtually impossible Rockwool on the other hand would be a lot more practical to install. I’m just wondering whether the joists being 4 inches are too shallow? Thanks in advance

Thanks for the information, Sparrowhawk. Time is running out for me we have found a buyer for our current home and in around two months will have to move so establishing a heating system has become mission critical. You asked if it has original skirts and Plastere yes it does have done or I’m doing a sympathetic renovation. It has 11 inch skirting boards downstairs and installing underfloor heating would raise the floor level by 3 cm losing some of the skirting board height which also niggles me. The space to cover is 106 m² and I would propose to install it myself and have an engineer hook it up to the boiler that is if it’s going to be economical to run I cannot afford making a here because running cost of a house of the size of significant and my salary is not a significant one so I have to make the right choice. If it’s not going to save me on my bills, then there’s no point in doing it and I should continue to seek out to cast iron radiators to install and retain the Period character of the house. Nonetheless, I do want it but is wanting it merit enough to install it. Another issue is finding cast iron radiator is big enough for each room. It’s proving to be very difficult so I may have to install two smaller Custom irons rather than one big one.

Still expense, I think you might be right he asked me to go and get the measurements of the rooms for him, but he didn’t ask for the window sizes or anything

Thanks again my boiler engineer has done the heat loss analysis and these are the requirements for Btu

Thank you both so it could be more expensive to run underfloor heating than appropriately sized and installed radiators unless I add a mass of insulation to the subfloor is that what I am to understand? if I installed underfloor heating, it would be to reduce the monthly expenditure on Gas and also for the comfort factor if it’s not going to save me anything in terms of running costs I may as well do as you suggest and stick with radiators

Thank you for the valued input. The boiler has already been installed. It is a 35 kW condensing. Vailent I’m not sure of the model number right now. another thing I’d like to clarify about the suspended floors and the heat loss downwards. Are you sure that even an overlay system for underfloor heating would suffer heat loss downwards? This is contrary to what the manufacturers advice and I’m becoming confused so I came on here for independent advice. I’m very much the point of making the decision and pulling the trigger and if radiators run in the way you suggest all the better option then I will continue as planned and travel around the country collecting cast iron radiators for their historical appeal and their performance

Hello everyone We are in the process of sympathetically renovating a large Edwardian three story semidetached house and we are considering underfloor heating for the ground floor. The property benefits from double glazing and an open plan area of approximately 70 m² consisting of a lounge area plan extension with bifold windows and an kitchen separated by a single wall. The property has a traditional suspended wooden floor and we are considering an overlay system such as those supplied by Wunda. The materials quotation has come back as favourable however I see complications running the 35 kW valent boiler with Custom iron radiators in the upper floor and underfloor heating on the ground floor. The idea for this is to reduce energy costs as well as comfort. The alternative is to run cast iron radiators downstairs and upstairs at Delta 40. I need some help with the best solution for our house as I have no experience within the floor heating let alone running a radiator system upstairs and an underfloor heating system downstairs. Any help and advice would be gratefully received? Is it going to be worth the cost and installation of underfloor heating over and above that of cast iron radiators. Will I be able to effectively run radiators and on the floor heating off the same boiler? It’s decision time now so any help gratefully appreciated. just to add that the rear of the property where the bifold windows are and the extension is has all been insulated in accordance with current building regulations the front half of the property and upstairs is traditionally built