Ext Insulation on old cottage walls and warm roof over current flat roof - on solid extn to back

harry999

I got the above quote to do external insulate on 100 m2 1950's cottage (the cottage has a solid wall extension to rear with flat roof as below) Just wondering what people think of this quote - I think it is a lot of money... Any recommendations for Ext insulation companies in Munster ? Can anything be dropped from this quote ?(we cannot afford above - he also has a heat pump which i told him to leave out) The rubber on the warm flat roof is this a good job ? It has just 5 years guarantee - which I a bit concerned about.

Flat roof below => Thanks

Dudda

The flat roof is slightly on the cheap side probably due to a cheap covering. It sounds like its going to be done right tying into the pitched room and includes all new rainwater goods.

For supply, fit, plaster and new window boards the windows are good value unless they're are small ones which would make it a reasonable quote. I'd be interested in the spec sheet for them.

The ventilation could be expensive but if the toilets are all over the place and access for ducts is difficult it could be reasonable too.

You've no roof lights? None in the quote anyway.

Without seeing the house and plans in general everything is about right. Its a lot of work your planning so was never going to be cheap.

10-10-20

I'll just mention that the ventilation system is an MEV (mechanical extract ventilation) system and it operates by pulling air out of the kitchen and wet rooms by drawing air in via the room vents and window vents. In this case you'll feel colder air being pulled in, requiring additional heating. If there is any option in the budget I believe that you would be better off with mechanical heat recovery ventilation (MHRV). I think that MHRV could be limited in your case if the flat roof remains as there won't be sufficient space for it to be installed. Others here may be able to correct me there.

The differences between each system are shown here:

MEV:

https://www.cleanenergyireland.ie/mechanical-extract-ventilation/

MHRV:

https://www.ventilationsupplies.ie/residential-ventilation-mechanical-ventilation-with-heat-recovery.php

This is just guidance in your best interest. I hope it helps.

harry999

Thanks for replies => The house has just one toilet on first floor... Yes no roof lights - but bedroom + bathroom under flat roof have windows - so roof light probably not needed - none on current roof either...

satellite view of house - so it is a 1950's cottage with porch at front and extn to rear with flat roof... Thks

harry999

I was hoping to spend 70k - is there anything I could take out of quote ? or any good company in Munster I could ask then for a quote? Thks

10-10-20

Oh, so the flat roof is the double-height extension at the rear.

To be honest, whats quoted seems to be a relatively complete job and dropping any one aspect could leave you lacking in some areas.

I'll just ask if you know what's included in the 12k for the pitched roof insulation with skimed finish? That's not clear, are you converting the attic or what? Could that be rolled back to just installing 300mm of glass-wool?

Just be careful on that as the builder has quoted without seeing the attic... so costs could easily go north on that.

Shoog

I live in a similar bungalow. 600mm thick massed concrete walls and pitched roof touching the wall plate. With 10ft walls the top 1ft of vertical wall and 2ft of horizontal wall top thickness are not accessable to insulate which represents about 30% of the total wall surface been a cold bridge. As such external wall insulation is almost the worst approach I could consider without removing the roof and capping off the top of the wall with insulation.

Internal wall with dropped insulated ceilings is a far better solution.

If yours is a similar setup, think about it.

harry999

The attic insulation of cottage pitch roof 13k - seem very expensive - could I drop this and I put rolls of rock wool insulation myself ?

The gas boiler in the house needs replacing - so would I be better off putting a Air to Water heat pump system in for 25k and I get an seai grant of 10,500 ? Or put in a new gas boiler for 3.5k ?

Also the quote for scaffolding - is it normal to have this separate ? The ext insulation of 32k - should this not have the scaffolding included

Thanks

harry999

If I just do external insulation on the solid block extension part of house to the back - it should reduce the cost of ext insulation by 50%. The cottage walls are stone build wide walls and will have some insulation ....& if damp on any area inside I can just insulate inside on this area ? Would this work ? Thanks

Shoog

Old cottages often have inadequate foundations and DPC which means covering them over in any way can cause damp problems. There are ways of using breathable insulations such as hemp and lime but they tend to be expensive and I am not certain they can match the effectiveness of other methods.

There maybe issues with eaves ventilation with regard to attic insulation which would be part of any insulation job. Simply stuffing more rock wool into the space can lead to damp and rot.

Scaffolding is horribly expensive and rented by the day. Also it needs weekly inspections which is another cost. It was the main reason I decided not to attempt external insulation on our renovation project.

Without more details it's hard to assess what issues exist on your particular project. Needless to say even simple jobs are expensive so any issues can send cost sky rocketing.

I would be looking for a few more quotes and then compare them for the issues they have highlighted. They should be consistent across the board and if they are not you have identified the questions you need to be asking of the contractor. It's the sortmof area where the cost of a good engineer or architect could save you a packet in the long run.

10-10-20

https://www.boards.ie/discussion/comment/121383636#Comment_121383636

Scaffolding is separate as it's usually handled by an external supplier, only some builders have their own. Another quote may not include it, hence it's worth getting multiple quotes.

Do ask them for a breakdown on that pitched roof insulation or see why rolled glass wool would not be sufficient.

https://www.boards.ie/discussion/comment/121383847#Comment_121383847

I wouldn't, it would be a half-job and you'd regret it. The MEV may depend on the whole house being insulated and relatively airtight.