The heat feedback profile across 5cm wide, 15cm tall samples of PMMA is measured as a flame spreads vertically across its surface. Incident heat flux to a water cooled gauge is determined with peak values averaging to 36kW/m^2 across the height of the sample. This heat flux has been separated into its convective and radiative components and, at this scale, radiative heat transfer is shown to account for between 5 and 15% of total flame to surface heat flux. Based on these measurements, net heat flux into the pyrolyzing material can be determined. Correlations, expressed solely as a function of sample burning rate, predicting net heat feedback to the material's surface are developed.