FAQ's
Here is a selection of the most Frequently Asked Questions about underfloor heating.
Question?
Answer?
1. WHAT TYPE OF FLOOR INSULATION IS REQUIRED?
It is essential that floors which are ground bearing or suspended over an un-heated space with or without underfloor heating are properly insulated to meet the U-values requirements as stated in the Building Regulations Part L1/L2 2002. The value is currently set at 0.25 W/m 2K. The thickness of insulation required to achieve this will vary according to the type of floor, size of floor and type of insulation selected. Generally, an insulation with a high thermal resistance is preferable, to reduce the build height of the total floor construction.
2. WHAT ABOUT BOILER SIZE & HEAT OUTPUTS?
Boilers are normally sized according to heat load requirement from the heat loss calculation in the normal way and also taking account of other requirements such as domestic hot water. If normal thermostatic on/off controls are used then it is advisable to use a larger (20 - 25%) boiler to speed up the re-heat times. As a guide, the heat output available from a Radiant UFH system is 100W/m 2 for a solid floor and 70W/m 2 for a timber suspended floor.
3. WHAT TYPE OF BOILER / TYPE OF FUEL CAN BE USED?
Generally any type of boiler or any type of fuel can be used as a heat source. Condensing boilers are certainly worth considering because the low return water temperature often means that the boiler operates in deep condensing mode.
(Note: some oil fired boilers may not be suitable where there is a small heat output requirement)
4. WHAT DO I DO IF THE FLOOR IS NOT GETTING HOT ENOUGH (OR TOO HOT)?
Increase flow temperature or flow rate (decrease flow temperature / flow rate). The UFH water temperature can be adjusted by changing the water temperature thermostatic valve (Basic Control Pack). The flow rate can be adjusted using the Lockshield valve on return manifold. Turn clockwise to reduce flow or anti clockwise to increase flow.
5. IS IT SUITABLE FOR WOODEN FLOORS?
In Scandinavia, timber floors are extremely popular and are increasing in popularity in our country. Chipboard floors which form the base for carpet or vinyl finishes can be used without special consideration due to the stability of their construction. Similarly, laminated strips or boards are designed to be unaffected by shrinkage due to moisture changes. Real wood finishes, however, are natural materials and may be subject to shrinkage or expansion as the moisture content of the wood changes. The use of underfloor heating need not cause problems providing wood with moisture content below 10% is selected and correctly stored before use. A marginal change in gapping between boards may be evident between the heating season and when the heating is not in use.
6. ARE ALL TYPES OF VINYL, CARPET AND UNDERLAY OKAY?
These materials can be laid over screeded or timber covered floors. Maximum floor temperatures for vinyl type materials can be limited to those recommended by the manufacturer but a lower heat output may result. When selecting underlays for carpets, bear in mind that the use of dense or very thick underlays may also restrict the heat output from the floor. Radiant can advise on the best type of underlay to use.
7. WHAT TYPE OF SCREED IS REQUIRED? WHAT THICKNESS?
There is no special requirement for the screed. For domestic applications, use a fine sand / cement mix (to BS 8204) with a minimum thickness of 65mm. Radiant recommends that wherever possible the thickness of the screed is 75mm. No special screed additives are necessary. Anhydryite screeds and other types of flow screeds can be kept to a nominal thickness of 55mm and will not have an adverse effect on the pipe.
8. IS THE PIPE AFFECTED BY HEATING SYSTEM ADDITIVES?
Normal additives, such as Fernox and Senitel, will not affect the pipe. The integral oxygen diffusion barrier of the multi-layer pipe totally excludes oxygen permeation through the pipe wall. This prevents oxidation of metal components in the system and helps to reduce maintenance costs.
9. IS RADIANT MULTI-LAYERED PIPE DIFFICULT TO INSTALL?
No, Radiant Pipe is easy to install, once you bend it to the required shape it stays in that shape, unless you want to change it. The pipe is laid out as indicated on the easy to follow CAD drawings which we provide. The only joints required are at the manifold which is all above floor level.
10. WILL I BE WARM ENOUGH?
Provided the building meets the minimum insulation standards as laid down by current Building Regulations, Radiant UFH will provide full comfort conditions. Floor temperatures will not normally exceed 29°C which means that the floor will feel comfortable.
11. IS IT EXPENSIVE TO BUY / RUN?
It is a competitively priced system when compared to good quality or special radiators (such as a Low Surface Temperature Radiator), used in certain applications. Independent tests carried out on operating efficiencies suggest that UFH can be up to 26% more efficient than radiators.
12. WE HAVE RADIATORS BUT CAN WE PUT UFH IN OUR EXTENSION AND CONSERVATORY?
Yes, the design of the system and the controls available means UFH can fully integrate with your existing heating system. The Room controller can allow individual room heating so the conservatory can be kept warmer than other rooms in the house if desired. Radiant can supply a range of fittings and equipment to connect an underfloor system to any standard installation.
13. IS IT SUITABLE FOR OLDER BUILDINGS OR RESTORATIONS?
Yes, Radiant UFH can be retro-fitted if floor boards are accessible, or if the floor can be raised slightly or if the floor is being replaced. It is ideal for fitting in older buildings with high ceilings that could not be heated practically by other systems.
14. WHAT HAPPENS IF THE PIPE GETS DAMAGED?
If the Radiant multi-Layered pipe is damaged, it can be restored to its original state by carefully reshaping the pipe with smooth jawed grips to regain the original dimensions. If the pipe is punctured it can be replaced, if accessible, or repaired using a high integrity pipe repair coupling supplied with all Radiant UFH systems. This will not affect the pipe guarantee.
15. IS THE PIPE SAFE?
Yes, Radiant multi-Layered pipe is perfectly safe. It is non-toxic and can operate at temperatures as low as -100°C to over +100°C and pressures up to 10 bar (approximately 145psi).
If you have any other additional questions, please contact our Office or, where appropriate, your UFH Designer, for fast friendly help. |
